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Barros J, Winkler FM, Velasco LA. Assessing the genetic diversity in Argopecten nucleus (Bivalvia: Pectinidae), a functional hermaphrodite species with extremely low population density and self-fertilization: Effect of null alleles. Ecol Evol 2020; 10:3919-3931. [PMID: 32489620 PMCID: PMC7244797 DOI: 10.1002/ece3.6080] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 11/15/2022] Open
Abstract
Argopecten nucleus is a functional hermaphroditic pectinid species that exhibits self-fertilization, whose natural populations have usually very low densities. In the present study, the genetic diversity of a wild population from Neguanje Bay, Santa Marta (Colombia), was estimated using microsatellite markers, and the effect of the presence of null alleles on this estimation was assessed. A total of 8 microsatellite markers were developed, the first described for this species, and their amplification conditions were standardized. They were used to determine the genotype of 48 wild individuals from Naguanje Bay, and 1,010 individuals derived from the offspring of 38 directed crosses. For each locus, the frequencies of the identified alleles, including null alleles, were estimated using the statistical package Micro-Checker, and the parental genotypes were confirmed using segregation analysis. Three to 8 alleles per locus with frequencies from 0.001 to 0.632 were detected. The frequencies of null alleles ranged from 0.10 to 0.45, with Ho from 0.0 to 0.79, and He from 0.53 to 0.80. All loci were in H-W disequilibrium. The null allele frequencies values were high, with lower estimations using segregation analysis than estimated using Micro-Checker. The present results show high levels of population genetic diversity and indicate that null alleles were not the only cause of deviation from H-W equilibrium in all loci, suggesting that the wild population under study presents signs of inbreeding and Wahlund effect.
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Affiliation(s)
- Judith Barros
- Laboratorio de Moluscos y MicroalgasUniversidad del MagdalenaSanta MartaColombia
| | - Federico M. Winkler
- Departamento de Biología MarinaFacultad de Ciencias del MarUniversidad Católica del NorteCoquimboChile
- Centro de Innovación Acuícola AquaPacíficoCoquimboChile
- Centro de Estudios Avanzados en Zona Áridas (CEAZA)CoquimboChile
| | - Luz Adriana Velasco
- Laboratorio de Moluscos y MicroalgasUniversidad del MagdalenaSanta MartaColombia
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2
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Flanagan SP, Jones AG. The future of parentage analysis: From microsatellites to SNPs and beyond. Mol Ecol 2019; 28:544-567. [PMID: 30575167 DOI: 10.1111/mec.14988] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/14/2022]
Abstract
Parentage analysis is a cornerstone of molecular ecology that has delivered fundamental insights into behaviour, ecology and evolution. Microsatellite markers have long been the king of parentage, their hypervariable nature conferring sufficient power to correctly assign offspring to parents. However, microsatellite markers have seen a sharp decline in use with the rise of next-generation sequencing technologies, especially in the study of population genetics and local adaptation. The time is ripe to review the current state of parentage analysis and see how it stands to be affected by the emergence of next-generation sequencing approaches. We find that single nucleotide polymorphisms (SNPs), the typical next-generation sequencing marker, remain underutilized in parentage analysis but are gaining momentum, with 58 SNP-based parentage analyses published thus far. Many of these papers, particularly the earlier ones, compare the power of SNPs and microsatellites in a parentage context. In virtually every case, SNPs are at least as powerful as microsatellite markers. As few as 100-500 SNPs are sufficient to resolve parentage completely in most situations. We also provide an overview of the analytical programs that are commonly used and compatible with SNP data. As the next-generation parentage enterprise grows, a reliance on likelihood and Bayesian approaches, as opposed to strict exclusion, will become increasingly important. We discuss some of the caveats surrounding the use of next-generation sequencing data for parentage analysis and conclude that the future is bright for this important realm of molecular ecology.
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Affiliation(s)
- Sarah P Flanagan
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Adam G Jones
- Department of Biological Sciences, University of Idaho, Moscow, Idaho
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3
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Willoughby JR, Wijayawardena BK, Sundaram M, Swihart RK, DeWoody JA. The importance of including imperfect detection models in
eDNA
experimental design. Mol Ecol Resour 2016; 16:837-44. [PMID: 27037675 DOI: 10.1111/1755-0998.12531] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Janna R. Willoughby
- Department of Forestry and Natural Resources Purdue University 715 W. State St. West Lafayette IN 47907 USA
- Department of Biological Sciences Purdue University 915 W. State St. West Lafayette IN 47907 USA
| | - Bhagya K. Wijayawardena
- Department of Biological Sciences Purdue University 915 W. State St. West Lafayette IN 47907 USA
| | - Mekala Sundaram
- Department of Forestry and Natural Resources Purdue University 715 W. State St. West Lafayette IN 47907 USA
| | - Robert K. Swihart
- Department of Forestry and Natural Resources Purdue University 715 W. State St. West Lafayette IN 47907 USA
| | - J. Andrew DeWoody
- Department of Forestry and Natural Resources Purdue University 715 W. State St. West Lafayette IN 47907 USA
- Department of Biological Sciences Purdue University 915 W. State St. West Lafayette IN 47907 USA
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4
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Fernández-Cruz J, Fernández-López J. Genetic structure of wild sweet chestnut (Castanea sativa Mill.) populations in northwest of Spain and their differences with other European stands. CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0835-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Hoban S, Anderson R, McCleary T, Schlarbaum S, Romero-Severson J. Thirteen nuclear microsatellite loci for butternut (Juglans cinerea L.). Mol Ecol Resour 2013; 8:643-6. [PMID: 21585858 DOI: 10.1111/j.1471-8286.2007.02030.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Butternut (Juglans cinerea L.) is an eastern North American forest tree severely threatened by an exotic fungal pathogen, Sirococcus clavigignenti-juglandacearum. We report here 13 nuclear microsatellites for genetic evaluation of the remaining natural populations. Summary statistics are reported for individuals from a population of butternuts in central Kentucky (N = 63). All markers were polymorphic, with an average of 13.7 alleles per locus observed. Four loci exhibited significantly fewer heterozygotes than expected under Hardy-Weinberg equilibrium (P < 0.05).
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Affiliation(s)
- Sean Hoban
- University of Notre Dame, Department of Biological Sciences, Notre Dame, IN 46556, USA, 7899 County Road 3950, West Plains, Missouri 65775, USA, Department of Forestry, Wildlife & Fisheries Institute of Agriculture, The University of Tennessee, Knoxville, Knoxville, TN 37996-4563, USA
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6
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[Microsatellite markers for parentage identification in Jian Carp (Cyprinus carpio var. Jian)]. YI CHUAN = HEREDITAS 2012. [PMID: 23208142 DOI: 10.3724/sp.j.1005.2012.01447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Using 16 microsatellite loci we estimated the parentage of 647 progeny in 10 Jian Carp full-sib families. Cervus 3.0 analysis showed that mean PIC value of 16 microsatellites, mean number of allele, and mean expected heterozygosity were 0.7025, 6.63, and 0.7405, respectively. The combined probability of exclusion was 0.99922456 when both parents were unknown and the combined probability of exclusion was 0.99999557 when only one of the parental genotype was known, with the confidence level of 95%. Further simulations based on allele frequencies suggested that to achieve the requirements of paternity test usually took 8 to 12 microsatellite loci when both parents were unknown and 5 to 8 microsatellite loci when one parent was known. Out of 647 progenies, 94.6% were assigned to their parental pairs without the information of both parents in parentage analysis, which were lower than the theoretical assignment rates predicted by the Cervus simulations. This could be explained by the relationship between the candidate parents or existence of null and by typing errors. The identification of 9 families was useful for linkage analysis of Jian Carp and QTL location, also for marker assisted selection for economical traits.
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7
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Zhuo X, Liang R, Chen Y, Huang G, Yu D, Zou J. Genetic characterization of northern snakehead (Channa argus) populations in China using microsatellite markers. BIOCHEM SYST ECOL 2012. [DOI: 10.1016/j.bse.2012.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Kim WJ, Kong HJ, Shin EH, Kim CH, Kim HS, Kim YO, Nam BH, Kim BS, Lee SJ, Jung HT. Isolation and inheritance of microsatellite loci for the oily bittering (Acheilognathus koreensis): applications for analysis of genetic diversity of wild populations. Anim Cells Syst (Seoul) 2012. [DOI: 10.1080/19768354.2011.645554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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9
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Archie EA, Chiyo PI. Elephant behaviour and conservation: social relationships, the effects of poaching, and genetic tools for management. Mol Ecol 2011; 21:765-78. [PMID: 21880086 DOI: 10.1111/j.1365-294x.2011.05237.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Genetic tools are increasingly valuable for understanding the behaviour, evolution, and conservation of social species. In African elephants, for instance, genetic data provide basic information on the population genetic causes and consequences of social behaviour, and how human activities alter elephants' social and genetic structures. As such, African elephants provide a useful case study to understand the relationships between social behaviour and population genetic structure in a conservation framework. Here, we review three areas where genetic methods have made important contributions to elephant behavioural ecology and conservation: (1) understanding kin-based relationships in females and the effects of poaching on the adaptive value of elephant relationships, (2) understanding patterns of paternity in elephants and how poaching can alter these patterns, and (3) conservation genetic tools to census elusive populations, track ivory, and understand the behavioural ecology of crop-raiding. By comparing studies from populations that have experienced a range of poaching intensities, we find that human activities have a large effect on elephant behaviour and genetic structure. Poaching disrupts kin-based association patterns, decreases the quality of elephant social relationships, and increases male reproductive skew, with important consequences for population health and the maintenance of genetic diversity. In addition, we find that genetic tools to census populations or gather forensic information are almost always more accurate than non-genetic alternatives. These results contribute to a growing understanding of poaching on animal behaviour, and how genetic tools can be used to understand and conserve social species.
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Affiliation(s)
- Elizabeth A Archie
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
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10
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Development, characterization, and inheritance of 113 novel EST-SSR markers in the Pacific oyster (Crassostrea gigas). Genes Genomics 2011. [DOI: 10.1007/s13258-011-0021-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Chang DS, An HS, Oh TY, Lee JB, Park JY, Kim KK. Eleven new microsatellite markers in jack mackerel (Trachurus japonicus) derived from an enriched genomic library. Genes Genomics 2009. [DOI: 10.1007/bf03191852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Fernández-de-Mera IG, Vicente J, Pérez de la Lastra JM, Mangold AJ, Naranjo V, Fierro Y, de la Fuente J, Gortázar C. Reduced major histocompatibility complex class II polymorphism in a hunter-managed isolated Iberian red deer population. J Zool (1987) 2009. [DOI: 10.1111/j.1469-7998.2008.00524.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Isolation and characterization of polymorphic microsatellite markers for the black rockfishSebastes inermis. Genes Genomics 2009. [DOI: 10.1007/bf03191135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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14
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SEABRA SOFIAG, QUARTAU JOSÉA, BRUFORD MICHAELW. Spatio-temporal genetic variation in sympatric and allopatric Mediterranean Cicada species (Hemiptera, Cicadidae). Biol J Linn Soc Lond 2009. [DOI: 10.1111/j.1095-8312.2008.01116.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Yu H, Li Q. Exploiting EST Databases for the Development and Characterization of EST–SSRs in the Pacific Oyster (Crassostrea gigas). J Hered 2008; 99:208-14. [DOI: 10.1093/jhered/esm124] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Kanno M, Suyama Y, Li Q, Kijima A. Microsatellite analysis of Japanese sea cucumber, Stichopus (Apostichopus) japonicus, supports reproductive isolation in color variants. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2006; 8:672-85. [PMID: 17043749 DOI: 10.1007/s10126-006-6014-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Accepted: 06/05/2006] [Indexed: 05/12/2023]
Abstract
The genetic relationship among the three color variants (Red, Green, and Black) of the Japanese sea cucumber, S. japonicus, was investigated using 11 microsatellite markers. Genetic differentiation testing among the three sympatric color types showed the strong heterogeneity of Red (p<0.001), while no significant difference was observed between Green and Black (p=0.301 to 0.961). UPGMA trees constructed from 10 sample lots from 5 localities showed two distinct clusters, one from the Red types and the other from the Green and Black types. In addition, the sympatric Green and Black formed one subcluster with strong bootstrap support at each locality. These results indicate the separate species status of Red and the other color types, and also support the population identity of sympatric Green and Black.
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Affiliation(s)
- Manami Kanno
- Laboratory of Integrative Aquatic Biology, Graduate School of Agriculture Science, Tohoku University, Onagawa, Miyagi, 9862242, Japan
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17
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Zhang Q, Allen SK, Reece KS. Genetic variation in wild and hatchery stocks of Suminoe Oyster (Crassostrea ariakensis) assessed by PCR-RFLP and microsatellite markers. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2005; 7:588-99. [PMID: 16027991 DOI: 10.1007/s10126-004-5105-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Accepted: 03/07/2005] [Indexed: 05/03/2023]
Abstract
Genetic variation in wild Asian populations and U.S. hatchery stocks of Crassostrea ariakensis was examined using polymerase chain reactions with restriction fragment length polymorphism (PCR-RFLP) analysis of both the mitochondrial COI gene and the nuclear internal transcribed spacer (ITS) 1 region and using 3 microsatellite markers. Hierarchical analysis of molecular variance and pairwise comparisons revealed significant differentiation (P < 0.05) between samples from the northern region, represented by collections from China and Japan, and 2 of 3 samples from southern China. PCR-RFLP patterns were identified that were diagnostic for the northern (N-type) and southern (S-type) groups. Microsatellite marker profiles were used to assign each oyster to one of the two northern or two southern populations. Results for more than 97% of the oysters were consistent with the PCR-RFLP patterns observed for each individual in that oysters with N-type patterns were assigned to one of the northern populations and those with S-type patterns to one of the southern populations. At one site of the Beihai (B) region in southern China a mix of individuals with either the N-type or S-type PCR-RFLP genotypes was found. No heterozygotes at the nuclear ITS-1 locus were found in the sample, possibly indicating reproductive isolation in sympatry. Microsatellite assignment test results of the B individuals were also consistent with identifications as either the N-type or S-type based on PCR-RFLP patterns. The parental population for one hatchery stock was this B sample, which initially was composed of almost equal numbers of northern and southern genetic types. After hatchery spawns, however, more than 97% of the progeny fell into the northern genetic group by PCR-RFLP and microsatellite assignment test analyses, indicating that the individuals with the southern genotype contributed little to the spawn, owing to gametic incompatibility, differential larval survival, or a difference in timing of sexual maturity. Overall, results suggested that oysters collected as C. ariakensis in this study, and likely in other studies as well, include two different sympatric species with some degree of reproductive isolation.
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Affiliation(s)
- Qian Zhang
- Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA
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18
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Kanno M, Li Q, Kijima A. Isolation and characterization of twenty microsatellite loci in Japanese sea cucumber (Stichopus japonicus). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2005; 7:179-83. [PMID: 15906112 DOI: 10.1007/s10126-004-0006-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Accepted: 05/27/2004] [Indexed: 05/02/2023]
Abstract
Twenty microsatellite markers were first developed from the Japanese sea cucumber Stichopus japonicus using an enrichment protocol. Of the 20 microsatellite loci, 19 loci were polymorphic in the population examined. At these polymorphic loci, the number of alleles per locus varied from 2 to 15, and the observed heterozygosities ranged from 0.03 to 0.97, which is considerably higher than those previously found for allozymes. The high variability of the microsatellite markers identified in this study will make them excellent tools for genetic analyses of S. japonicus.
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Affiliation(s)
- Manami Kanno
- Integrated Center of Field Sciences, Graduate School of Agricultural Science, Tohoku University, Onagawa, Miyagi, 986-2242, Japan
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19
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Abstract
Highly polymorphic microsatellite markers are widely employed in population genetic analyses (eg, of biological parentage and mating systems), but one potential drawback is the presence of null alleles that fail to amplify to detected levels in the PCR assays. Here we examine 233 published articles in which authors reported the suspected presence of one or more microsatellite null alleles, and we review how these purported nulls were detected and handled in the data analyses. We also employ computer simulations and analytical treatments to determine how microsatellite null alleles might impact molecular parentage analyses. The results indicate that whereas null alleles in frequencies typically reported in the literature introduce rather inconsequential biases on average exclusion probabilities, they can introduce substantial errors into empirical assessments of specific mating events by leading to high frequencies of false parentage exclusions.
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Affiliation(s)
- E E Dakin
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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20
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McCartney MA, Acevedo J, Heredia C, Rico C, Quenoville B, Bermingham E, McMillan WO. Genetic mosaic in a marine species flock. Mol Ecol 2004; 12:2963-73. [PMID: 14629377 DOI: 10.1046/j.1365-294x.2003.01946.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We used molecular approaches to study the status of speciation in coral reef fishes known as hamlets (Serranidae: Hypoplectrus). Several hamlet morphospecies coexist on Caribbean reefs, and mate assortatively with respect to their strikingly distinct colour patterns. We provide evidence that, genetically, the hamlets display characteristics common in species flocks on land and in freshwaters. Substitutions within two mitochondrial DNA (mtDNA) protein-coding genes place hamlets within a monophyletic group relative to members of two related genera (Serranus and Diplectrum), and establish that the hamlet radiation must have been very recent. mtDNA distances separating hamlet morphospecies were slight (0.6 +/- 0.04%), yielding a coalescent estimate for the age of the hamlet flock of approximately 430 000 years. Morphospecies did not sort into distinct mtDNA haplotype phylogroups, and alleles at five hypervariable microsatellite loci were shared broadly across species boundaries. None the less, molecular variation was not distributed at random. Analyses of mtDNA haplotype frequencies and nested clades in haplotype networks revealed significant genetic differences between geographical regions and among colour morphospecies. We also observed significant microsatellite differentiation between geographical regions and in Puerto Rico, among colour morphospecies; the latter providing evidence for reproductive isolation between colour morphospecies at this locale. In our Panama collection, however, colour morphospecies were mostly genetically indistinguishable. This mosaic pattern of DNA differentiation implies a complex interaction between population history, mating behaviour and geography and suggests that porous boundaries separate species in this flock of brilliantly coloured coral reef fishes.
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Affiliation(s)
- Michael A McCartney
- Department of Biological Sciences, 601 S. College Road., University of North Carolina at Wilmington, Wilmington NC 28403, USA.
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21
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Evolutionary history of Ash Meadows pupfish (genus Cyprinodon) populations inferred using microsatellite markers. CONSERV GENET 2004. [DOI: 10.1007/s10592-004-1978-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Abstract
The recent proliferation of hypervariable molecular markers has ushered in a surge of techniques for the analysis of parentage in natural and experimental populations. Consequently, the potential for meaningful studies of paternity and maternity is at an all-time high. However, the details and implementation of the multifarious techniques often differ in subtle ways that can influence the results of parentage analyses. Now is a good time to reflect on the available techniques and to consider their strengths and weaknesses. Here, we review the leading techniques in parentage analysis, with a particular emphasis on those that have been implemented in readily useable software packages. Our survey leads to some important insights with respect to the utility of the different approaches. This review should serve as a useful guide to anyone who wishes to embark on the study of parentage.
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Affiliation(s)
- Adam G Jones
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA.
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23
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Abstract
The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widely reported over the past 25 years. A large load of deleterious recessive mutations could explain both phenomena, according to the dominance hypothesis of heterosis. Using inbred lines derived from a natural population of Pacific oysters and classical crossbreeding experiments, we compare the segregation ratios of microsatellite DNA markers at 6 hr and 2-3 months postfertilization in F(2) or F(3) hybrid families. We find evidence for strong and widespread selection against identical-by-descent marker homozygotes. The marker segregation data, when fit to models of selection against linked deleterious recessive mutations and extrapolated to the whole genome, suggest that the wild founders of inbred lines carried a minimum of 8-14 highly deleterious recessive mutations. This evidence for a high genetic load strongly supports the dominance theory of heterosis and inbreeding depression and establishes the oyster as an animal model for understanding the genetic and physiological causes of these economically important phenomena.
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Affiliation(s)
- S Launey
- University of California, Davis, Bodega Marine Laboratory, Bodega Bay, California 94923-0247, USA
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Flagstad O, Olsaker I, Røed KH. The use of heterologous primers for analysing microsatellite variation in hartebeest Alcelaphus buselaphus. Hereditas 1999; 130:337-40. [PMID: 10509144 DOI: 10.1111/j.1601-5223.1999.00337.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- O Flagstad
- Department of Biology, University of Oslo, Norway.
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