Parent-of-origin specific QTL--a possibility towards understanding reciprocal effects in chicken and the origin of imprinting

Reciprocal effects for sexual maturity, egg production, egg quality traits and viability are well known in poultry crosses. They have been used in an optimal way to form profitable production hybrids. These effects have been hypothesized to originate from sex-linked genes, maternal effects or a combination of both. However, these may not be the only explanations for reciprocal effects. Recent mapping of quantitative trait loci (QTL) has revealed autosomal areas with parent-of-origin specific effects in the chicken. In mammals, parental imprinting, i.e. the specifically regulated expression of either maternal or paternal allele in the offspring, is the main cause of such effects. The most commonly accepted hypothesis for the origin of imprinting, the conflict hypothesis, assumes a genetic conflict of interest between the maternal and paternal genomes regarding the allocation of resources to the offspring. It also intrinsically implies that imprinting should not occur in oviparous taxa. However, new molecular genetic information has raised a need to review the possible involvement of imprinting or some related phenomena as a putative cause of reciprocal effects in poultry. Comparative mapping provides strong evidence for the conservation of orthologous imprinted gene clusters on chicken macrochromosomes. Furthermore, these gene clusters exhibit asynchronous DNA replication, an epigenetic mark specific for all imprinted regions. It has been proposed that these intrinsic chromosomal properties have been important for the evolution of imprinted gene expression in the mammalian lineage. Many of the mapped parent-of-origin specific QTL effects in chicken locate in or close to these conserved regions that show some of the basic features involved in monoallelic expression. If monoallelic expression in these regions would be observed in birds, the actual mechanism and cause may be different from the imprinting that evolved later in the mammalian lineage. In this review we discuss recent molecular genetic results that may provide tools for understanding of reciprocal differences in poultry breeding and the evolution of imprinting.

Infertile Finnish Yorkshire boars carry a full-length LINE-1 retrotransposon within the KPL2 gene

The KPL2 gene is expressed predominantly in cells with cilia or flagella. We have previously demonstrated that a large intronic insertion in KPL2 is associated with immotile sperm cells and infertility in the domesticated pig (Sus scrofa). To fully characterize the structure of the mutation, we have now cloned and sequenced the insertion. The data identified the presence of a long interspersed nuclear element-1 (LINE-1) encoding all activities required for retrotransposition, including a 5'-untranslated region (UTR) with an internal RNA polymerase II promoter, two open reading frames (ORF1 and ORF2) separated by an intergenic region and a 3' UTR containing a polyadenylation signal. Characterization of the junctions between the LINE-1 and the genomic target revealed the presence of direct repeats of 14 bp at both ends, showing that integration occurred by target-primed reverse transcription. Furthermore, sequence analysis suggested that the aberrant splicing pattern of KPL2 transcripts induced by the LINE-1 element is caused by interference with putative intronic splice signals and activation of a cryptic splice site. These data demonstrate that integration of a transposition-competent L1 element into KPL2 is responsible for the defective spermatozoa, which accentuates the role of mobile DNA elements as insertional mutagens in mammalian genomes.

Birth of correctly genotyped calves after multiplex marker detection from bovine embryo microblade biopsies

We report a method for multiplex genotyping of bovine embryo microblade biopsies. We have tested the reliability of the method and the viability of the embryos in vitro and in vivo. Two polymorphic gene markers (GHR F279Y and PRLR S18N) associated with milk production traits and one marker for sex diagnosis (ZFX/ZFY) were genotyped simultaneously with a method that combines nested PCR and allelic discrimination. To test the accuracy of genotyping, in the first experiment the genotypes of 134 biopsies from in vitro produced embryos were compared to genotypes determined from the corresponding embryos after biopsy. The method proved to be highly accurate as only in three cases (two for PRLR S18N and one for GHR F279Y) out of 395 genotypes the genotype was in disagreement between the two samples. The viability of similarly biopsied embryos was tested in parallel: after 24-hr culture 94.6% of embryos recovered in vitro. In the second experiment, a total of 150 in vivo-produced embryos were biopsied on Day 7 and genotyped. After the genotyping results were obtained on Day 8, female embryos were selected for transfer. From a total of 57 selected embryos 43 were transferred individually and 14 as pairs. After single embryo transfers, 19 recipients became pregnant and after embryo transfers in pairs one became pregnant. The success of genotyping was tested with the genotypes of donors and bulls and also from the hair samples of born calves. All calves were females and of the same genotypes determined from the biopsy.

Prioritization for conservation of northern European cattle breeds based on analysis of microsatellite data

Northern European indigenous cattle breeds are currently endangered and at a risk of becoming extinct. We analyzed variation at 20 microsatellite loci in 23 indigenous, 3 old imported, and 9 modern commercial cattle breeds that are presently distributed in northern Europe. We measured the breeds' allelic richness and heterozygosity, and studied their genetic relationships with a neighbor-joining tree based on the Chord genetic distance matrix. We used the Weitzman approach and the core set diversity measure of Eding et al. (2002) to quantify the contribution of each breed to the maximum amount of genetic diversity and to identify breeds important for the conservation of genetic diversity. We defined 11 breeds as a "safe set" of breeds (not endangered) and estimated a reduction in genetic diversity if all nonsafe (endangered) breeds were lost. We then calculated the increase in genetic diversity by adding one by one each of the nonsafe breeds to the safe set (the safe-set-plus-one approach). The neighbor-joining tree grouped the northern European cattle breeds into Black-and-White type, Baltic Red, and Nordic cattle groups. Väne cattle, Bohus Poll, and Danish Jersey had the highest relative contribution to the maximum amount of genetic diversity when the diversity was quantified by the Weitzman diversity measure. These breeds not only showed phylogenetic distinctiveness but also low within-population variation. When the Eding et al. method was applied, Eastern Finncattle and Lithuanian White Backed cattle contributed most of the genetic variation. If the loss of the nonsafe set of breeds happens, the reduction in genetic diversity would be substantial (72%) based on the Weitzman approach, but relatively small (1.81%) based on the Eding et al. method. The safe set contained only 66% of the observed microsatellite alleles. The safe-set-plus-one approach indicated that Bohus Poll and Väne cattle contributed most to the Weitzman diversity, whereas the Eastern Finncattle contribution was the highest according to the Eding et al. method. Our results indicate that both methods of Weitzman and Eding et al. recognize the importance of local populations as a valuable resource of genetic variation.

ApoE genotype and cognition after subarachnoid haemorrhage: a longitudinal study

OBJECTIVES

To investigate the effect of the apolipoprotein epsilon4 allele on cognitive functions after aneurysmal subarachnoid haemorrhage (SAH) in a longitudinal study.

MATERIALS AND METHODS

Performances of 19 patients with and 27 patients without the epsilon4 allele were compared on eight cognitive test variables measured 1-4.5 years and 12-15 years after SAH.

RESULTS

In the baseline examination, epsilon4 patients scored worse than non-epsilon4 patients on verbal fluency (P < 0.05). In the follow-up, a visual memory task and interference in colour naming showed more pronounced impairments from baseline in epsilon4 carriers than in non-carriers.

CONCLUSION

Presence of the epsilon4 allele poses a minor risk for late cognitive impairment after the subacute phase of aneurysmal SAH.

Transplantation of normal boar testicular cells resulted in complete focal spermatogenesis in a boar affected by the immotile short-tail sperm defect

Transplantation of testicular cells, also known as spermatogonial stem cell transplantation, is a relatively new approach in the field of male infertility. We used this technique to determine whether donor-derived sperm production in unrelated porcine recipients is possible following ultrasound-guided transfer of testicular cells. This study was undertaken because we had a strain of Finnish Yorkshire boars with a hereditary recessive gene defect rendering all spermatozoa immotile and anatomically abnormal in homozygous boars. Thus, monitoring of the focal success of colonization of donor spermatogonia with subsequent production of progressively motile spermatozoa was extremely sensitive. Testicular cells from young normal crossbred boars were transplanted into the testes of two boars affected with the immotile short-tail sperm (ISTS) defect. Prior to the transplantations, busulfan was used to suppress recipients' endogenous spermatogenesis. The ejaculates were collected and analysed for the presence of motile spermatozoa. In one of the two recipient boars transplanted with testicular cells from normal donors, motile spermatozoa appeared in the ejaculates 12 weeks after the transplantation. Spermatozoa manually selected under a microscope from a frozen aliquot of ejaculate collected 27 weeks after transplantation were genotyped. In two of the 20 vials the donor-derived genotype was visible. The genotyping results substantiated the success - as indicated by the appearance of motile spermatozoa after the spermatogonial transfer. Thus, donor-derived sperm production in unrelated recipients is possible. In addition, the production after transplantation of progressively motile spermatozoa with normal tail lengths shows that the ISTS defect in Finnish Yorkshire boars apparently results from defective transcription of an essential gene for sperm motility in germline cells. To conclude, the transplantation of donor testicular cells can, at least in boars with the ISTS defect, result in complete focal spermatogenesis.

The role of the bovine growth hormone receptor and prolactin receptor genes in milk, fat and protein production in Finnish Ayrshire dairy cattle

We herein report new evidence that the QTL effect on chromosome 20 in Finnish Ayrshire can be explained by variation in two distinct genes, growth hormone receptor (GHR) and prolactin receptor (PRLR). In a previous study in Holstein-Friesian dairy cattle an F279Y polymorphism in the transmembrane domain of GHR was found to be associated with an effect on milk yield and composition. The result of our multimarker regression analysis suggests that in Finnish Ayrshire two QTL segregate on the chromosomal region including GHR and PRLR. By sequencing the coding sequences of GHR and PRLR and the sequence of three GHR promoters from the pooled samples of individuals of known QTL genotype, we identified two substitutions that were associated with milk production traits: the previously reported F-to-Y substitution in the transmembrane domain of GHR and an S-to-N substitution in the signal peptide of PRLR. The results provide strong evidence that the effect of PRLR S18N polymorphism is distinct from the GHR F279Y effect. In particular, the GHR F279Y has the highest influence on protein percentage and fat percentage while PRLR S18N markedly influences protein and fat yield. Furthermore, an interaction between the two loci is suggested.

An intronic insertion in KPL2 results in aberrant splicing and causes the immotile short-tail sperm defect in the pig

The immotile short-tail sperm defect is an autosomal recessive disease within the Finnish Yorkshire pig population. This disease specifically affects the axoneme structure of sperm flagella, whereas cilia in other tissues appear unaffected. Recently, the disease locus was mapped to a 3-cM region on porcine chromosome 16. To facilitate identification of candidate genes, we constructed a porcine-human comparative map, which anchored the disease locus to a region on human chromosome 5p13.2 containing eight annotated genes. Sequence analysis of a candidate gene KPL2 revealed the presence of an inserted retrotransposon within an intron. The insertion affects splicing of the KPL2 transcript in two ways; it either causes skipping of the upstream exon, or causes the inclusion of an intronic sequence as well as part of the insertion in the transcript. Both changes alter the reading frame leading to premature termination of translation. Further work revealed that the aberrantly spliced exon is expressed predominantly in testicular tissue, which explains the tissue-specificity of the immotile short-tail sperm defect. These findings show that the KPL2 gene is important for correct axoneme development and provide insight into abnormal sperm development and infertility disorders.

Estimation of breed contributions to present and future genetic diversity of 44 North Eurasian cattle breeds using core set diversity measures

Extinction of breeds threatens genetic diversity of livestock species. The need to conserve genetic diversity is widely accepted but involves in general two questions: (i) is the expected loss of diversity in a set of breeds within a defined future time horizon large enough to establish a conservation plan, and if so (ii) which breeds should be prioritised for such a conservation plan? The present study uses a marker assisted methodology to address these questions. The methodology combines core set diversity measures with a stochastic method for the estimation of expected future diversity and breed marginal diversities. The latter is defined as the change in the total diversity of all breeds caused by a one unit decrease in extinction probability of a particular breed. The stochastic method was validated by means of simulations. A large field data set consisting of 44 North Eurasian cattle breeds was analysed using simplified determined extinction probabilities. The results show that the expected loss of diversity in this set within the next 20 to 50 years is between 1 and 3% of the actual diversity, provided that the extinction probabilities which were used are approximately valid. If this loss is to be reduced, it is sufficient to include those three to five breeds with the highest marginal diversity in a conservation scheme.

A region on chicken chromosome 2 affects both egg white thinning and egg weight

We describe the results from genetic dissection of a QTL region on chicken chromosome 2, shown to affect egg weight and quality in an earlier genome scan of an F₂ intercross between two divergent egg layer lines. As the 90% confidence intervals for the detected QTL covered tens of centiMorgans, new analyses were needed. The datasets were reanalysed with denser marker intervals to characterise the QTL region. Analysis of a candidate gene from the original QTL region, vimentin, did not support its role in controlling egg white thinning. Even after reanalysis with additional seven markers in the QTL area, the 90% confidence intervals remained large or even increased, suggesting the presence of multiple linked QTL for the traits. A grid search fitting two QTL on chromosome 2 for each trait suggested that there are two distinct QTL areas affecting egg white thinning in both production periods and egg weight in the late production period. The results indicate possible pleiotropic effects of some of the QTL on egg quality and egg weight. However, it was not possible to make a distinction between close linkage versus pleiotropic effects.

Fishy taint in chicken eggs is associated with a substitution within a conserved motif of the gene

Fishy odor of urine and other secretions is a characteristic of trimethylaminuria in humans, resulting from loss-of-function mutations in the flavin-containing mono-oxygenase isoform FMO3. A similar phenotype exists in cattle, in which a nonsense mutation in the bovine orthologue causes fishy off-flavor in cow's milk. The fishy odor is caused by an elevated level of excreted odorous trimethylamine (TMA), due to deficient oxidation of TMA. We report the mapping of a similar disorder (fishy taint of eggs) and the chicken FMO3 gene to chicken chromosome 8. The only nonsynonymous mutation identified in the chicken FMO3 gene (T329S) changes an evolutionarily highly conserved amino acid and is associated with elevated levels of TMA and fishy taint in the egg yolk in several chicken lines. No differences in the expression of FMO3 were found among individuals with different associated genotypes, indicating that the trait is not caused by a linked polymorphism causing altered expression of the gene. The results support the importance and function of the evolutionarily conserved motif FATGY, which has been speculated to be a substrate recognition pocket of N-hydroxylating siderophore enzymes and flavin-containing mono-oxygenases.

Quantitative trait loci with parent-of-origin effects in chicken

We investigated potential effects of parent-of-origin specific quantitative trait loci (QTL) in chicken. Two divergent egg-layer lines differing in egg quality were reciprocally crossed to produce 305 F2 hens. Searching the genome using models with uni-parental expression, we identified four genome-wide significant QTL with parent-of-origin effects and three highly suggestive QTL affecting age at first egg, egg weight, number of eggs, body weight, feed intake, and egg white quality. None of these QTL had been detected previously using Mendelian models. Two genome-wide significant and one highly suggestive QTL show exclusive paternal expression while the others show exclusive maternal expression. Each of the parent-of-origin specific QTL explained 3-5 % of the total phenotypic variance, with the effects ranging from 0.18 to 0.4 phenotypic SD in the F2. Using simulations and further detailed analyses, it was shown that departure from fixation in the founder lines, grand-maternal effects (i.e. mitochondrial or W-linked) and Z-linked QTL were unlikely to give rise to any spurious parent-of-origin effects. The present results suggest that QTL with parent-of-origin specific expression are a plausible explanation for some reciprocal effects in poultry and deserve more attention. An intriguing hypothesis is whether these effects could be the result of genomic imprinting, which is often assumed to be unique to eutherian mammals.

Comparison of microsatellite and blood protein diversity in sheep: inconsistencies in fragmented breeds

Finnsheep, Romanov, Oxford Down and three local breeds from Finland or northwestern Russia were assessed at 15 microsatellite and 7 protein loci. A novel albumin allele was identified. Diversity patterns were mostly concordant between marker types, but discrepancies appeared for the local Viena and Vepsia sheep, both demonstrating frequent linkage disequilibria for both marker types and excess of homozygotes for microsatellites, and in the case of Vepsia also for proteins as signs of breed fragmentation. On the basis of microsatellite data, the neighbour-joining tree and two-dimensional map constructed from DA distances suggested that difference in longitude of breed origin would relate to breed relationship, whereas on the basis of protein data latitude would have this quality. These different impressions resulted because genetic distances involving Vepsia sheep were relatively low for protein variation compared with microsatellites. Microsatellite variation correlated positively with protein variation, but for the local Viena sheep protein variation was comparatively low. Populations had significant differences in allelic richness, but not in genetic diversity. Analysis implied that at least 30 polymorphic loci were needed to detect a difference in diversity between populations using a paired t-test, if the true mean diversity difference was 0.2. In the total sample, proteins demonstrated larger theta-values, but this was reversed for Finnsheep, for which model-based clustering of microsatellite genotypes revealed a structure associated with coat colour. Imported and rare sheep exhibited lowered allelic variability and increased frequency of pairwise disequilibria between unlinked markers. Our results emphasize that more loci are required for studying fragmented breeds.

Molecular dissection of a quantitative trait locus: a phenylalanine-to-tyrosine substitution in the transmembrane domain of the bovine growth hormone receptor is associated with a major effect on milk yield and composition

We herein report on our efforts to improve the mapping resolution of a QTL with major effect on milk yield and composition that was previously mapped to bovine chromosome 20. By using a denser chromosome 20 marker map and by exploiting linkage disequilibrium using two distinct approaches, we provide strong evidence that a chromosome segment including the gene coding for the growth hormone receptor accounts for at least part of the chromosome 20 QTL effect. By sequencing individuals with known QTL genotype, we identify an F to Y substitution in the transmembrane domain of the growth hormone receptor gene that is associated with a strong effect on milk yield and composition in the general population.

Mapping of quantitative trait loci affecting quality and production traits in egg layers

A mapping population segregating for egg quality traits was created by a line cross between two egg layer lines and screened by a genome scan. The F2 generation consisted of 307 hens, which were scored for egg quality and production traits. The mapping population was genotyped for 99 microsatellite loci, spanning nine macrochromosomes and five small linkage groups. The linkage maps were used in mapping QTL affecting 14 traits, by using multiple markers and a least-squares approach. We detected 14 genomewide significant and six suggestive QTL that were located on chromosomes 2, 3, 4, 5, and, 8 and sex chromosome Z. A significant QTL affecting egg white thinning was found on chromosome 2. For eggshell strength, a significant QTL was found on chromosome Z. For production traits, the most interesting area was on chromosome 4, where highly significant QTL effects were detected for BW, egg weight, and feed intake in the same area. The most significant QTL explains 25.8% of the phenotypic variance in F2 of body weight. An area affecting the age at first egg, egg weight, and the number of eggs was located on chromosome Z.

Sex determination of bovine embryo blastomeres by fluorogenic probes

One of the major challenges of using genetic information in marker assisted selection (MAS) is the detection of multiple marker loci from a small biopsy sample of a preimplantation stage embryo. The objective of this study was to develop a fast, nested, multiplex preamplification, polymerase chain reaction (PCR) method for the determination of sex in bovine embryo blastomeres. For this aim, ZFX/ZFY sequences were preamplified simultaneously with other genomic regions. The preamplification product was used as a template in an allelic discrimination assay, with nested primers and sex specific fluorogenic probes for ZFX and ZFY. Fluorogenic probes were used to eliminate the need for time consuming electrophoresis. Compared to sexing with Bovy/kappa-casein co-amplification method and other replicates from the same embryo, the accuracy of sexing with the use of fluorogenic probes after preamplification was 99% (112/113 blastomeres). The amplification efficiency was 96% (113/117 blastomeres).

Simultaneous mining of linkage and linkage disequilibrium to fine map quantitative trait loci in outbred half-sib pedigrees: revisiting the location of a quantitative trait locus with major effect on milk production on bovine chromosome 14

A maximum-likelihood QTL mapping method that simultaneously exploits linkage and linkage disequilibrium and that is applicable in outbred half-sib pedigrees is described. The method is applied to fine map a QTL with major effect on milk fat content in a 3-cM marker interval on proximal BTA14. This proximal location is confirmed by applying a haplotype-based association method referred to as recombinant ancestral haplotype analysis. The origin of the discrepancy between the QTL position derived in this work and that of a previous analysis is examined and shown to be due to the existence of distinct marker haplotypes associated with QTL alleles having large substitution effects.

Mapping of an immotile short tail sperm defect in the Finnish Yorkshire on porcine Chromosome 16

An immotile short tail sperm defect has recently been identified as a hereditary disorder present within the Finnish Yorkshire pig population. The syndrome is inherited as an autosomal recessive disease exclusively expressed in male individuals as shorter sperm tail length and immotile spermatozoa. Based on the assumption of a recent common origin of the disease-causing mutation, a genome-wide search was performed with 228 evenly spaced microsatellites by homozygosity mapping of affected and unaffected DNA pools. One locus, SW2411 on Chr 16, demonstrated a significantly skewed allele distribution between the two pools. Linkage analysis of five markers in this region mapped the disease-causing gene within a 6-cM confidence interval region with a highest LOD score of 7.7 at marker SW419. It appears that three-marker haplotypes can be used for marker-assisted selection within analyzed pedigrees. Furthermore, future fine mapping may reveal a more precise population-wide associated haplotype and facilitate identification of a new gene affecting sperm tail development.

Quantitative trait loci affecting clinical mastitis and somatic cell count in dairy cattle

Norway has a field recording system for dairy cattle that includes recording of all veterinary treatments on an individual animal basis from 1978 onwards. Application of these data in a genome search for quantitative trait loci (QTL) verified genome-wise significant QTL affecting clinical mastitis on Chromosome (Chr) 6. Additional putative QTL for clinical mastitis were localized to Chrs. 3, 4, 14, and 27. The comprehensive field recording system includes information on somatic cell count as well. This trait is often used in selection against mastitis when direct information on clinical mastitis is not available. The absence of common QTL positions for the two traits in our study indicates that the use of somatic cell count data in QTL studies aimed for reducing the incidence of mastitis should be carefully evaluated.

Predictors of discharge to home during the first year after right hemisphere stroke

OBJECTIVES

The aim of this study was to explore predictive factors of the length of hospital stay at the acute stage of right hemisphere stroke. Special attention was paid to the possible role of anosognosia for hemiparesis and anosognosia for neglect in this prediction.

PATIENTS AND METHODS

A consecutive series of 57 patients having their first right hemisphere stroke were examined at the acute phase. Forty-nine patients were included in this study and followed-up for 12 months. The examinations were conducted within 2 weeks of onset. The outcome variable was the time (days) from stroke to discharge to home. The predictors were age, gender, size of infarct, neglect, hemiparesis, verbal memory, unawareness of illness, anosognosia for neglect, anosognosia for hemiparesis and presence of a relative at home.

RESULTS

Hemiparesis and unawareness of illness lengthened the duration of the hospital stay, the presence of a relative reduced it. Neglect was the best single predictor of poor outcome, but it had no additional value in the combination of the three predictors above. Neither anosognosia for hemiparesis nor anosognosia for neglect were important predictors.

CONCLUSION

Hemiparesis, unawareness of illness and presence of a relative at home were the best predictors of the time from right hemisphere stroke to discharge to home.

Adverse long-term effects of brain radiotherapy in adult low-grade glioma patients

OBJECTIVE

To study the long-term effects of radiotherapy on cognitive function in adult patients operated on for low-grade glioma.

METHODS

A cohort of 160 patients who underwent surgery for low-grade gliomas of cerebral hemisphere between 1980 and 1992 in a single institution serving a defined population was studied. At a mean follow-up time of 7 years, 28 of the 101 patients who had postoperative irradiation (and no second surgery or chemotherapy) were still alive and eligible for MRI and neuropsychological study. Twenty-three of 59 patients who did not have radiotherapy, second surgery, or chemotherapy were alive and eligible at a mean of 10 years.

RESULTS

The group that had postoperative irradiation performed significantly worse than the group that did not in cognitive tests. This difference was not accounted for by histologic diagnosis; location, extent of removal, or progression of the tumor; or any patient factor. Leukoencephalopathy was more severe in the group that had postoperative irradiation than in the group without radiotherapy, and correlated to poor memory performances only in the postoperative radiotherapy group. Average Karnofsky performance scale score was significantly lower in the group that had postoperative irradiation than in the group that did not.

CONCLUSION

In adults with low-grade glioma, postoperative radiotherapy poses a significant risk of long-term leukoencephalopathy and cognitive impairment.

Mapping of multiple quantitative trait loci by simple regression in half-sib designs

Detection of QTL in outbred half-sib family structures has mainly been based on interval mapping of single QTL on individual chromosomes. Methods to account for linked and unlinked QTL have been developed, but most of them are only applicable in designs with inbred species or pose great demands on computing facilities. This study describes a strategy that allows for rapid analysis, involving multiple QTL, of complete genomes. The methods combine information from individual analyses after which trait scores for a specific linkage group are adjusted for identified QTL at other linkage groups. Regression methods are used to estimate QTL positions and effects; permutation tests are used to obtain empirical threshold values. The description of the methods is complemented by an example of the combined analysis of 28 bovine chromosomes and their associations with milk yield in Finnish Ayrshire cattle. In this example, the individual analysis revealed five suggestive QTL affecting milk yield. Following the strategy presented in this paper, the final combined analysis showed eight significant QTL affecting milk yield. This clearly demonstrates the potential gain of using the combined analysis. The use of regression methods, with low demands on computing resources, makes this approach very practical for total genome scans.

Unawareness of deficits after right hemisphere stroke: double-dissociations of anosognosias

OBJECTIVES

The aim was to study whether anosognosia for hemiparesis, anosognosia for neglect and general unawareness of illness double-dissociate, indicating that anosognosias are specific and independent impairments of awareness. On the other hand, anosognosias may be associated with one another and with general cognitive dysfunction, which decreases awareness of deficits. The persistence and predictive value of anosognosias was examined during a 1-year follow-up.

PATIENTS AND METHODS

Fifty-seven consecutive patients with acute right hemisphere infarction underwent neurological and neuroradiological examinations, neuropsychological testing and an interview 10 days, 3 months and 1 year after onset.

RESULTS

Anosognosia for neglect and anosognosia for hemiparesis double-dissociated, as did unawareness of illness and anosognosia for neglect. Patients showing unawareness of illness or anosognosia for neglect and anosognosia for hemiparesis had poorer orientation and verbal memory than patients who were aware of these defects. Unawareness of illness and anosognosia for hemiparesis disappeared during 3-month follow-up.

CONCLUSION

Double-dissociations demonstrate that anosognosias for different defects are independent and specific impairments of awareness, although general cognitive disorder may also reduce awareness of defects. Unawareness of illness and anosognosia for hemiparesis disappear rapidly and can hardly be direct causes of poor long-term recovery. However, transient anosognosia may be associated with persistent disorders which result in poor outcome.

Genetic diversity and population structure of 20 North European cattle breeds

Blood samples were collected from 743 animals from 15 indigenous, 2 old imported, and 3 commercial North European cattle breeds. The samples were analyzed for 11 erythrocyte antigen systems, 8 proteins, and 10 microsatellites, and used to assess inter- and intrabreed genetic variation and genetic population structures. The microsatellites BoLA-DRBP1 and CSSM66 were nonneutral markers according to the Ewens-Watterson test, suggesting some kind of selection imposed on these loci. North European cattle breeds displayed generally similar levels of multilocus heterozygosity and allelic diversity. However, allelic diversity has been reduced in several breeds, which was explained by limited effective population sizes over the course of man-directed breed development and demographic bottlenecks of indigenous breeds. A tree showing genetic relationships between breeds was constructed from a matrix of random drift-based genetic distance estimates. The breeds were classified on the basis of the tree topology into four major breed groups, defined as Northern indigenous breeds, Southern breeds, Ayrshire and Friesian breeds, and Jersey. Grouping of Nordic breeds was supported by documented breed history and geographical divisions of native breeding regions of indigenous cattle. Divergence estimates between Icelandic cattle and indigenous breeds suggested a separation time of more than 1,000 years between Icelandic cattle and Norwegian native breeds, a finding consistent with historical evidence.

Visual neglect as a predictor of functional outcome one year after stroke

OBJECTIVE

The aim was to study the role of visual neglect in acute right hemisphere brain infarct as a predictor of poor functional outcome during the first year after stroke. In particular, we were interested in the additional value of neglect measures besides hemiparesis, hemianopia, cognitive deficits and age.

PATIENTS AND METHODS

A consecutive series of 57 patients with a neuroradiologically verified right hemisphere infarct was examined within 10 days of the stroke. Fifty patients were followed up for 1 year. Neglect was measured with the Conventional and the Behavioural subtests of the Behavioural Inattention Test (BITC and BITB, respectively). The predictors were determined at the 10-day examination. Functional outcome was assessed 3, 6 and 12 months after the onset with the Frenchay Activities Index.

RESULTS

Neglect in BITB was the best single predictor, which together with high age formed the best combination of predictors for poor functional outcome at each follow-up. Hemiparesis was also included in this prediction model at the 3-month follow-up, but hemianopia, BITC, or visuoconstructional and memory deficits showed no additional predictive value. However, neglect usually recovered soon. When neurological and cognitive deficits were assessed at the same time as the outcome, hemiparesis rather than neglect was the strongest correlate of poor outcome.

CONCLUSION

Neglect in acute stroke is an important predictor of poor functional recovery. Residual neglect, which could be compensated in the follow-up tests, may nevertheless restrict patients' real-life activities and hobbies.

A quantitative trait locus for live weight maps to bovine chromosome 23

A multiple-marker mapping approach was used to search for quantitative trait loci (QTLs) affecting production, health, and fertility traits in Finnish Ayrshire dairy cattle. As part of a whole-genome scan, altogether 469 bulls were genotyped for six microsatellite loci in 12 families on Chromosome (Chr) 23. Both multiple-marker interval mapping with regression and maximum-likelihood methods were applied with a granddaughter design. Eighteen traits, belonging to 11 trait groups, were included in the analysis. One QTL exceeded experiment level and one QTL genome level significance thresholds. Across-families analysis provided strong evidence (P(experiment) = 0.0314) for a QTL affecting live weight. The QTL for live weight maps between markers BM1258 and BoLA DRBP1. A QTL significant at genome level (P(genome) = 0.0087) was mapped for veterinary treatment, and the putative QTL probably affects susceptibility to milk fever or ketosis. In addition, three traits exceeded the chromosome 5% significance threshold: protein percentage of milk, calf mortality (sire), and milking speed. In within-family analyses, protein percentage was associated with markers in one family (LOD score = 4.5).

Inaccurate prediction of retrieval in a face matrix learning task after right frontal lobe lesions

This study partly supports the hypothesis that frontal lobe lesions cause impairment of metamemory. Fifty-nine patients with a focal brain lesion and 21 non-brain-damaged patients memorized a 4 X 4 matrix of 16 faces in 6 consecutive trials and predicted the number of locations of faces they would be able to remember before each retrieval. When age-related impairment of learning was adjusted, the patients with right posterior lesions were inferior to the controls and to the patients with right frontal lesions on the total number of correctly placed faces. The patients with right frontal lesions were less accurate than the patients with right posterior lesions or the controls in the prediction of retrieval. The inaccuracy of retrieval prediction in the face test was associated with that in a word-list learning task.

Inaccurate prediction of retrieval in a face matrix learning task after right frontal lobe lesions

This study partly supports the hypothesis that frontal lobe lesions cause impairment of metamemory. Fifty-nine patients with a focal brain lesion and 21 non-brain-damaged patients memorized a 4 X 4 matrix of 16 faces in 6 consecutive trials and predicted the number of locations of faces they would be able to remember before each retrieval. When age-related impairment of learning was adjusted, the patients with right posterior lesions were inferior to the controls and to the patients with right frontal lesions on the total number of correctly placed faces. The patients with right frontal lesions were less accurate than the patients with right posterior lesions or the controls in the prediction of retrieval. The inaccuracy of retrieval prediction in the face test was associated with that in a word-list learning task.

Word list learning and prediction of recall after frontal lobe lesions

The effect of frontal lobe lesions on the accuracy of prediction of recall in a word list learning task was studied. Fifty-nine patients with a focal brain lesion and 21 non-brain-damaged control patients memorized a word list by selective reminding and predicted before each recall trial the number of words they would be able to recall. The patients with left frontal lesions, who were inferior to the patients with right frontal lesions and the control patients in word list recall, overpredicted their recall more than the other brain-damaged patients or the control patients, especially on the 1st trial. The patients with right frontal lesions were less accurate in the prediction of recall than the patients with right posterior lesions or the control patients.

Evaluation of genetic variability and genetic distances between eight chicken lines using microsatellite markers

The genetic variability and divergence of eight chicken lines were evaluated using nine microsatellite markers. The chicken lines included three White Leghorn hybrids, three Finnish Landrace lines, a Rhode Island Red line, and a broiler hybrid line. All the microsatellite loci were found to be polymorphic, the number of alleles varying from 4 to 13 per locus and 1 to 10 per line, respectively. Observed heterozygosities ranged from 0.00 to 0.91. The highest (0.67) and lowest (0.29) mean heterozygosity per line was observed in the broiler and in White Leghorn of Mäkelä, respectively. Three of the microsatellite loci deviated from the Hardy-Weinberg equilibrium in some populations. F statistics indicated clearly the subdivision of the total population into different lines. The genetic distances confirmed the classification of Finnish Landraces into different lines. A phylogenetic consensus tree was constructed from resampled data (1,000 times) using the neighbor-joining method. According to the phylogenetic tree, the lines were grouped into three clusters, in which the White Leghorns formed one group, two Landraces a second group, and a Landrace, the Rhode Island Red, and the broiler lines a third group. Allele distribution at the loci does not support either the stepwise or the infinite alleles mutation model, but the distribution pattern was quite irregular at different loci.

Word list learning and prediction of recall after frontal lobe lesions

The effect of frontal lobe lesions on the accuracy of prediction of recall in a word list learning task was studied. Fifty-nine patients with a focal brain lesion and 21 non-brain-damaged control patients memorized a word list by selective reminding and predicted before each recall trial the number of words they would be able to recall. The patients with left frontal lesions, who were inferior to the patients with right frontal lesions and the control patients in word list recall, overpredicted their recall more than the other brain-damaged patients or the control patients, especially on the 1st trial. The patients with right frontal lesions were less accurate in the prediction of recall than the patients with right posterior lesions or the control patients.

Neuropsychological Correlates of Duration of Glances at Secondary Tasks While Driving

The aim of this study was to find out the neuropsychological measures correlating with overlong glances at secondary in-car tasks while driving. Fifteen. patients with brain damage (without clear neurological or neuropsychological restriction on driving a car) and 11 healthy participants drove a route of 126 km and performed a series of secondary tasks while driving on a highway in an instrumented compact car. Four videocameras allowed detailed analysis of glances during in-car tasks. Neuropsychological measures focused on executive functions, memory, visuospatial skills, and fine motor skills. Moreover, patients' emotional self-evaluation and relatives' evaluation of patients' competencies were included. The proportion of overlong glances away from the road during in-car tasks was greater among the patients than. the healthy drivers. The long glances of the patients correlated strongly with motor and visuospatial deficits, cognitive inflexibility, emotional symptoms, and relatives' evaluations of patients' impaired sensomotor abilities. The results suggest that the frequency of overlong glances was increased by 2 factors: (a) impaired motor and visuospatial skills that evidently caused difficulties in the manipulation of the equipment of the secondary tasks, and (b) impairments of executive functions that were likely to decrease the ability to control the risks related to long glances at the in-car tasks. The slowing of speed during secondary tasks was on the average rather slight and not significantly more pronounced among patients than control drivers, indicating that patients failed to reduce their speed and thus the risk related to prolonged glances at in-car tasks.

Polymorphism within the 3' flanking region of the bovine growth hormone receptor gene

Growth hormone receptor (GHR) has a major role in the regulation of growth hormone action, and thus, is an obvious candidate gene associated with milk production traits in mammals. The present authors have sequenced 273 bp of the 3' flanking region of the bovine GHR, and found three length variants and one base substitution polymorphism in this region. Allele frequencies of the length variants differ between Finnish native and commercial dairy cattle breeds. The chromosomal localization of GHR was confirmed to bovine chromosome 20 by synteny mapping and linkage analysis.

Dual task performance after focal cerebral lesions and closed head injuries

The aim of this study was to demonstrate that focal frontal lobe lesions and closed head injuries cause a deficit in the deliberate minimizing of dual task decrements that follow when two separate tasks should be done concurrently. In single tasks, subjects counted backwards and cancelled visual targets as quickly and accurately as possible on separate 1 min trials. In the dual task, they were required to do both tasks simultaneously, taking care that performance on neither task would be notably more impaired than on the other, as only the performance showing a larger percentage decrement from the corresponding single task performance was taken into account as the result of the test. Patients with acute closed head injury displayed more pronounced dual task decrement than the controls. This deficit was not secondary to inefficiency on the single tasks but was related to the depth of coma at admission, the acuteness of injury and age. Contrary to expectation, patients with focal frontal lobe lesions or patients with subacute closed head injury did not demonstrate abnormal dual task decrement.

Frontal tests do not detect frontal infarctions after ruptured intracranial aneurysm

The series of 155 patients operated on for a ruptured intracranial arterial aneurysm was examined using typical frontal tests (the Stroop test, word fluency tasks, and a sorting task), as well as a learning and memory test. Patients with frontal infarction were not significantly inferior to patients with non-frontal infarction or to patients with no infarction. Frontal patients, however, were unable to return to work as often as non-frontal patients and more frequently than those with no infarction. These results indicate that the frontal tests used in this study are not selectively sensitive to mainly medial frontal infarctions that follow the rupture of an anterior cerebral artery aneurysm.

Cognitive decline in patients with symptomatic HIV-1 infection. No decline in asymptomatic infection

Thirty-six HIV-1-infected predominantly well-functioning subjects were followed up for one year by repeated neuropsychological, clinical neurological, neuroradiological, and immunological examinations. Changes in cognitive performance related to the severity of HIV-1 infection as well as to neuroradiological or immunological changes were studied. A decline in cognitive speed and flexibility was found in symptomatic subjects (ARC, AIDS). The impairment was especially pronounced in patients with progression of brain atrophy. These findings suggest a brain pathology underlying the cognitive decline in ambulatory outpatients with symptomatic HIV-1 infection. A practice effect was found in asymptomatic subjects (ASX, LAS) and in those with unchanged CT/MRI scans. No systematic relationship was found between cognitive change and immunological change.

Casein haplotypes and their association with milk production traits in the Finnish Ayrshire cattle

Polymorphism of casein genes was studied in half-sib families of artificial insemination bulls of the Finnish Ayrshire dairy breed. Ten grandsires and 300 of their sons were genotyped for the following polymorphisms: alpha s1-casein (B, C), beta-casein (A1, A2), the microsatellite within the kappa-casein gene (ms5, ms4) and kappa-casein (A, B, E). Nine different combinations of these alleles, casein haplotypes, were found. Associations between casein haplotypes and milk production traits (milk and protein yield, fat and protein percentage and milking speed) were studied with ordinary least-squares analysis to find a direct effect of the haplotypes or an association within individual grandsire families using the granddaughter design. Estimated breeding values of sons were obtained from cow evaluation by animal model. No direct effect of the casein haplotypes on the traits was found. Within grandsire families, in one out of four families the chromosomal segment characterized by haplotype 3 (B-A2-ms4-A) was associated with an increase in milk yield (P < 0.01) and a decrease in fat percentage (P < 0.01) when contrasted with haplotype 8 (B-A1-ms4-E). The results provide evidence that in the Finnish Ayrshire breed at least one quantitative trait locus affecting the genetic variation in yields traits is segregating linked to either haplotype 3 (B-A2-ms4-A) or 8 (B-A1-ms4-E).

Random amplified polymorphic DNA in cattle and sheep: application for detecting genetic variation

The present study investigated the use of the random amplified polymorphic DNA (RAPD) method to detect genetic variation in cattle and sheep. The animals studied consisted of samples from five Finnish cattle breeds: native Eastern (18 animals), Northern (24), Western Finncattle (24), Finnish Ayrshire (24), and Finnish Friesian (18); as well as a white (6 animals) and a grey (9) colour type of Finnsheep. The cattle and sheep populations were analysed with 11 and 13 RAPD primers demonstrating the most repeatable amplification pattern. Two out of ten RAPD fragments tested by cross hybridization showed homology between the two species. The RAPD method did not prove efficient for finding new polymorphisms in either species, because we found only three polymorphic RAPD markers for cattle and seven markers for sheep with different allele frequencies between the breeds. Although there is a greater presence of polymorphic RAPD markers in sheep, according to the similarity indices the sheep populations showed a higher degree of homogeneity than the cattle breeds. However, the interbreed and intrabreed similarity indices for cattle did not suggest any significant differentiation of the Finnish breeds, contrary to earlier results based on blood group and protein polymorphism.

Neuropsychology of mental programming: an approach for the evaluation of frontal lobe dysfunction

Patients with frontal lobe lesions tend to have poor psychosocial recovery, yet they may perform well on common cognitive tests. Their habitual cognitive skills seem to be preserved, whereas the purposeful utilization of skills in novel situations is impaired. This paper reviews neuropsychological disorders and models of mental programming. An approach for the evaluation of programming deficits is presented and some implications of the conception are considered. Programming is defined as the subjective optimization of subgoals for the achievement of the overall goal with available skills. It is posited that programming is critically dependent on prefrontal functions. Measures of programming were found to be sensitive to the effects of frontal lesions and closed-head injuries, as well as, to predict subsequent social recovery. Programming can be seen as an intermediate process between performance and motivation, the subjective optimization of subgoals integrates motivation and skills (operational resources) to purposeful activity.

Speed and flexibility on word fluency tasks after focal brain lesions

It was predicted that frontal lobe damaged patients are slower on word fluency tasks, especially on the generation of words beginning with a particular letter, and less flexible ("stuck-inset") on category alternation than patients with posterior lesions, whereas the latter commit a higher number of repetitions ("recurrent perseverations") than the former. Twenty-nine anterior and 31 posterior brain damaged patients were requested to say as quickly as possible (1) 20 animal names, (2) 10 words beginning with the letter S, and (3) alternately animals and S-words, 10 from each category without repeating the words already used in these tasks. The results failed to confirm the predictions.

Prediction of psychosocial recovery after head injury with cognitive tests and neurobehavioral ratings

A series of 53 patients was studied using a battery of tests and a neurobehavioral rating scale on average 4 months after closed-head injury (CHI). Social outcome was assessed 1 year after injury by interviewing a family member. The results supported the hypothesis that tests of flexibility and programming rather than tests of cognitive skills predict psychosocial recovery after CHI. Spatial Learning with Self-Set Goals and Sorting were measures of flexibility and programming. Contrary to expectation, word fluency performance was unrelated to these measures, but was associated with conventional intelligence tests, which did not predict psychosocial recovery. Cognition/Energy deficit on the Neurobehavioral Rating Scale and increased age were useful predictors of poor psychosocial outcome, whereas computed tomography findings or the Glasgow Coma Score were weakly related to the outcome indices. Evidently, cognitive flexibility and mental programming are very important psychological prerequisites of social recovery after CHI.

Cognitive flexibility and mental programming after closed head injuries and anterior or posterior cerebral excisions

Cognitive inflexibility and deficient mental programming are specifically related to frontal lobe lesions. The aim was to demonstrate that closed head injury (CHI) patients with brain lesions verified by computed tomography have such cognitive deficits, and are inferior in these respects to patients with posterior cerebral excisions mainly for tumours. This hypothesis was confirmed using a Category Identification and Sorting test as well as a measure of mental programming in a Spatial Learning task. Furthermore, CHI patients who had non-frontal parenchymal lesions were inferior by these measures to patients with posterior excisions. This result suggests that diffuse axonal lesion in CHI causes the deficits similar to those following frontal lobe excision.

Cognitive test performances related to early and late computed tomography findings after closed-head injury

Computed tomography (CT) findings from early (less than 24 hours) and late scan (6 months) after closed-head injury (CHI) were compared to cognitive test scores obtained on an average of 4 months after injury in a consecutive series of 53 patients. The presence of parenchymal lesion was associated with poor test results, indicating cognitive inflexibility and disinhibition of routine response tendencies in novel tasks. These deficits have previously been found to be related in particular to frontal-lobe dysfunction, but the present study did not support the hypothesis that frontal lesion is the principal cause of this impairment in CHI. Parenchymal lesions in the right and left hemisphere were associated with spatial and verbal deficits, respectively. Ventricular enlargement in the late CT was related to cognitive inefficiency, both being strongly associated with age. The results suggest that parenchymal lesion in the early CT is an indicator of diffuse axonal injury, which results in cognitive inflexibility during recovery.

A new mtDNA mutation associated with Leber hereditary optic neuroretinopathy

A single base mutation at nucleotide position 3460 (nt 3460) in the ND1 gene in human mtDNA was found to be associated with Leber hereditary optic neuroretinopathy (LHON). The G-to-A mutation converts an alanine to a threonine at the 52d codon of the gene. The mutation also abolishes an AhaII restriction site and thus can be detected easily by RFLP analysis. The mutation was found in three independent Finnish LHON families but in none of the 60 controls. None of the families with the nt 3460 mutation in ND1 had the previously reported nt 11778 mutation in the ND4 gene. The G-to-A change at nt 3460 is the second mutation so far detected in LHON.