A genetic map of bovine chromosome 7 with an interspecific hybrid backcross panel

Anti-Müllerian hormone as an endocrine biomarker of reproductive longevity and assessment of Single Nucleotide Polymorphisms in AMH gene of Bos indicus breeds of cattle

Anti-Müllerian hormone (AMH) is a member of the TGF-β superfamily produced by follicular granulosa cells (GCs) in women and cattle and is considered an endocrine biomarker of ovarian follicular reserve. The study examined how age and parity influence serum AMH concentration and investigated the presence of Single Nucleotide Polymorphisms in AMH gene in Bos indicus breeds viz Malnad Gidda Amritmahal and Hallikar. All five exons of AMH gene amplified by Polymerase Chain Reaction (PCR) were subjected to Sanger sequencing and identified important SNP and its effects. We observed a highly significant relationship between parity and AMH concentration in Amritmahal cattle, whereas Malnad Gidda and Hallikar breeds did not show a significant difference. We identified one SNP located in exon 5 (rs21402788) with base change A>G, a non-synonymous mutation resulting in a change in amino acid Q>R and the protein product. It is concluded that AMH level could be considered as an indicator of the ovarian reserve and productive herd life (longevity) irrespective of age/parity, especially in Bos indicus breeds of cattle.

Spatiotemporal expression pattern of miR-205, miR-26a-5p, miR-17-5p, let-7b-5p, and their target genes during different stages of corpus luteum in Egyptian buffaloes

Background

No doubt that the corpus luteum (CL) plays a vital role in the regulation of female cyclicity in mammals. The scenarios among microRNAs (miRNAs) and their target genes and steroid hormones {estradiol (E2) and progesterone (P4)} are required for better understanding the molecular regulation of CL during its formation, maturation, and regression. We aimed to (I) study the changes in the relative abundance of miR-205, miR-26a-5p, miR-17-5p, and let-7b-5p and their target genes: LHCGR, CASP3, PCNA, AMH, and PLA2G3, during different stages of corpus luteum in Egyptian buffaloes, and (II) and to address different scenarios between steroid concentrations in the serum and the expression pattern of selected miRNAs and their targets.

Methods

The paired ovaries and blood samples were collected from apparently healthy 50 buffalo cows at a private abattoir. The ovaries bearing CL were macroscopically divided according to their morphological structure and color into hemorrhagic (CLH), developing (CLD), mature (CLM), regressed (CLR), and albicans (CLA). Small pieces from different stages of CL (CLH, CLD, CLM, CLR, and CLA) were cut and immediately kept at − 80 °C for total RNA isolation and qRT-PCR. The serum was separated for steroid level estimation.

Results

The LHCGR was expressed during different stages of CL, and the peak of expression was at the mid-luteal stage. The CASP3 revealed a stage-specific response at different stages of CL. The PCNA has an essential role in cellular proliferation in buffaloes CL. Both expression patterns of PLA2G3 and AMH were found over the various developmental and regression stages. It was noticed that miR-205 is conserved to target LHCGR and CASP3 transcripts. Moreover, CASP3 and AMH were targeted via miR-26a-5p. Additionally, the CASP3 and PLA2G3 were targeted via let-7b-5p. The P4 level reached its peak during CLM. There were positive and negative strong correlations between miRNAs (miR-26a-5p and miR-205), target genes (LHCGR and CASP3) during different stages of CL, and steroid hormones in the serum.

Conclusions

Taken together, the orchestrated pattern among miRNAs, target genes, and steroid hormones is essential for maintaining the proper development and function of CL in buffalo cows.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00320-9.

Characterization of Anti-Müllerian Hormone (AMH) Gene in Buffaloes and Goats

The Anti-Müllerian Hormone (AMH) is a member of the transforming growth factor beta (TGF-β) superfamily, playing a significant role in cell proliferation, differentiation and apoptosis. In females, AMH is secreted throughout their reproductive life span from ovaries, whereas in males it is secreted by gonadal cells at a very early stage of testicular development. AMH is a promising marker of ovarian reserve in women and can be used to measure the female reproductive lifespan. In the present study, we cloned and sequenced the GC rich AMH gene from Indian riverine buffalo (Bubalus bubalis) and goat (Capra hircus). Obtained sequences were compared to the AMH sequences of other mammals, and corresponding amino acid sequences revealed that the caprine and bovine AMH sequences are more closely related to each other than to those of other mammals. Furthermore, we analyzed the chromosomal localization of AMH genes in mammalian species to understand potential syntenic relationship. The AMH gene is localized between the sequences for the SF3A and JSRP1 genes and maintains this precise location in relation to other nearby genes. The dN/dS ratio of AMH gene did not indicate any pressure for either positive or negative selection; thus, the physiological function of the AMH gene in the reproduction of these two ruminant species remains very vital. Similar to other mammals, the AMH gene may be an important indicator for regulating female reproductive biology function in bovine, cetacean, caprine, and camelidae.

AMH: Could It Be Used as A Biomarker for Fertility and Superovulation in Domestic Animals?

Anti-Müllerian hormone (AMH) is a reliable and easily detectable reproductive marker for the fertility competence of many farm animal species. AMH is also a good predictor of superovulation in cattle, sheep, and mares. In this review, we have summarized the recent findings related to AMH and its predictive reliability related to fertility and superovulation in domestic animals, especially in cattle. We focused on: (1) the dynamics of AMH level from infancy to prepubescence as well as during puberty and adulthood; (2) AMH as a predictor of fertility; (3) the association between antral follicle count (AFC) and plasma AMH level; (4) AMH as a predictor of superovulation; and (5) factors affecting AMH levels in domestic animals, especially cattle. Many factors affect the circulatory levels of AMH when considering the plasma, like nutrition, activity of granulosa cells, disease state and endocrine disruptions during fetal life. Briefly, we concluded that AMH concentrations are static within individuals, and collection of a single dose of blood has become more popular in the field of assisted reproductive technologies (ART). It may act as a potential predictor of fertility, superovulation, and ovarian disorders in domestic animals. However, due to the limited research in domestic animals, this potential of AMH remains underutilized.

Mapping Genes Is Good for You

I abandoned my original career choice of high school teaching to pursue dentistry and soon abandoned that path for genetics. The latter decision was due to a challenge by a professor that led to me reading Nobel speeches by pioneer geneticists before I had formal exposure to the subject. Even then, I was 15 years into my career before my interest in rodent genomes gave way to mapping cattle genes. Events behind these twists and turns in my career path comprise the first part of this review. The remainder is a review of the development of the field of bovine genomics from my personal perspective. I have had the pleasure of working with outstanding graduate students, postdocs, and colleagues to contribute my small part to a discipline that has evolved from a few individuals mapping an orphan genome to a discipline underlying a revolution in animal breeding.

Biological Functions and Clinical Applications of Anti-Müllerian Hormone in Stallions and Mares

Anti-Müllerian hormone (AMH) plays a major role in sexual differentiation, Leydig cell differentiation, and folliculogenesis. In addition, AMH has clinical value in equine practice. In stallions, AMH can serve as an endocrine marker for equine cryptorchidism and as an immunohistochemical marker for Sertoli cell tumors. Considering that AMH is also an ovarian specific product, intact mares can be differentiated from ovariectomized mares. Peripheral AMH concentrations reflect the follicular population in mares, and therefore, are useful in the assessment of ovarian reserve and reproductive life-span of aged mares. Last, AMH is particularly suitable as a diagnostic marker for equine granulosa cell tumors.

Conservation of genomic imprinting at the XIST, IGF2, and GTL2 loci in the bovine

Genomic imprinting is theorized to exist in all placental mammals and some marsupials; however, extensive comparative analysis of animals aside from humans and mice remains incomplete. Here we report conservation of genomic imprinting in the bovine at the X chromosome inactivation-specific transcript (XIST), insulin-like growth factor 2 (IGF2), and gene trap locus 2 (GTL2) loci. Coding single nucleotide polymorphisms (SNPs) between Bos gaurus and Bos taurus were detected at the XIST, IGF2, and GTL2 loci, which have previously been identified as imprinted in either humans, mice, or sheep. Expression patterns of parental alleles in F1 hybrids indicated preferential paternal expression at the XIST locus solely in the chorion of females, whereas analysis of the IGF2 and GTL2 loci indicated preferential paternal and maternal expression of alleles, respectively, in both fetal and placental tissues. Comparative sequence analysis of the XIST locus and adjacent regions suggests that repression of the maternal allele in the bovine is controlled by a different mechanism than in mice, further reinforcing the importance of comparative analysis of imprinting.

Epigenetic and genomic imprinting analysis in nuclear transfer derived Bos gaurus/Bos taurus hybrid fetuses

Somatic cell nuclear transfer (NT) in cattle is an inefficient process, whereby the production of calves is hindered by low pregnancy rates as well as fetal and placental abnormalities. Interspecies models have been previously used to facilitate the identification of single nucleotide polymorphisms (SNPs) within coding regions of genes to discriminate between parental alleles in the offspring. Here we report the use of a bovine interspecies model (Bos gaurus x Bos taurus) for the assessment and characterization of epigenetic modifications and genomic imprinting in Day 40-old female NT-derived fetuses and placenta. Analysis of NT and control pregnancies indicated disruption of genomic imprinting at the X inactivation-specific transcript (XIST) locus in the chorion, but not the fetus of clones, whereas proper allelic expression of the insulin-like growth factor II (IGF2) and gene trap locus 2 (GTL2) loci was maintained in both the fetus and placenta. Analysis of the XIST differentially methylated region (DMR) in clones indicated normal patterns of methylation; however, bisulfite sequencing of the satellite I repeat element and epidermal cytokeratin promoter indicated hypermethylation in the chorion of clones when compared with controls. No differences were detected in methylation levels in the fetus proper. These results indicate that the nuclear transfer process affects gene expression patterns in the trophectoderm- and inner cell mass-derived tissues to different extents.

AMH/MIS: what we know already about the gene, the protein and its regulation

(AMH/MIS) was first suggested by Jost, more than Four decades before this gonadal glycoprotein was purified and its gene and promoter sequenced. In mammals, AMH expression is triggered by SOX9 in Sertoli cells at the onset of testicular differentiation, and regulated by SF1, GATA factors, WT1, DAX1 and FSH. Ovarian granulosa cells also secrete AMH from late foetal life. In males, AMH is secreted into the bloodstream at high levels until puberty when it is down-regulated by androgens and meiotic germ cells and its directional secretion switches from the basal compartment to the seminiferous tubule lumen. In birds and reptiles, AMH expression shows particular features. Serum AMH determination is useful to study testicular function in boys and in patients with gonadal tumours. AMH levels in seminal and follicular fluid may also be of clinical use.

A deer (subfamily Cervinae) genetic linkage map and the evolution of ruminant genomes

Comparative maps between ruminant species and humans are increasingly important tools for the discovery of genes underlying economically important traits. In this article we present a primary linkage map of the deer genome derived from an interspecies hybrid between red deer (Cervus elaphus) and Père David's deer (Elaphurus davidianus). The map is approximately 2500 cM long and contains >600 markers including both evolutionary conserved type I markers and highly polymorphic type II markers (microsatellites). Comparative mapping by annotation and sequence similarity (COMPASS) was demonstrated to be a useful tool for mapping bovine and ovine ESTs in deer. Using marker order as a phylogenetic character and comparative map information from human, mouse, deer, cattle, and sheep, we reconstructed the karyotype of the ancestral Pecoran mammal and identified the chromosome rearrangements that have occurred in the sheep, cattle, and deer lineages. The deer map and interspecies hybrid pedigrees described here are a valuable resource for (1) predicting the location of orthologs to human genes in ruminants, (2) mapping QTL in farmed and wild deer populations, and (3) ruminant phylogenetic studies.

Parallel radiation hybrid mapping: a powerful tool for high-resolution genomic comparison

Comparative gene mapping in mammals typically involves identification of segments of conserved synteny in diverse genomes. The development of maps that permit comparison of gene order within conserved synteny has not advanced beyond the mouse map that takes advantage of linkage analysis in interspecific backcrosses. Radiation hybrid (RH) mapping provides a powerful tool for determining order of genes in genomes for which gene-based linkage mapping is impractical. Comparative RH mapping of 24 orthologous genes in this study revealed internal structural rearrangements between human chromosome 17 (HSA17) and bovine chromosome 19 (BTA19), two chromosomes known previously to be conserved completely and exclusively at level of synteny. Only six of the 24 genes had been previously ordered on the human G3 RH map. The use of the G3 panel to map the other 18, however, produced parallel RH maps for comparison of gene order at a resolution of <5 Mb on the bovine linkage map and from 1 to 3 Mb in the human physical map.

An integrated radiation hybrid map of bovine chromosome 19 and ordered comparative mapping with human chromosome 17

We recently constructed a 5000-rad cattle whole-genome radiation hybrid panel with the primary objective of integrating linkage maps of microsatellites with evolutionarily conserved genes into one ordered map. This study utilized the panel to construct a radiation hybrid (RH) map of bovine chromosome 19 (BTA19). Twelve microsatellites from different cattle linkage maps, 15 coding genes, and 2 expressed sequence tags were placed on the BTA19 RH map, with 16 of the markers ordered with odds of at least 1000:1. When the BTA19 RH map was compared with human chromosome 17 cytogenetic and RH maps, rearrangements in linear order were revealed for homologous genes on these two chromosomes that are totally conserved at the level of synteny mapping. Radiation hybrids, which have to date been used almost exclusively in mapping the human genome, are a potentially powerful resource for constructing maps for other species and for ordered comparative mapping between species.

Construction of a bovine chromosome 19 linkage map with an interspecies hybrid backcross

Interspecific hybrid backcross animals from a Bos taurus x Bos gaurus F1 female were used to construct a linkage map of bovine Chromosome (Chr) 19. This map includes eight previously unmapped type I anchor loci, CHRNB1, CRYB1, GH1, MYL4, NF1, P4HB, THRA1, TP53, and five microsatellite markers, HEL10, BP20, MAP2C, ETH3, BMC1013, from existing linkage maps. The linkage relationship was determined to be centromere-HEL10-18.8cM-NF1-4.0cM-CRYB1-11 .2cM-(BP20, CHRNB1, TP53)-4.0cM-(MAP2C, GH1, MYL4, THRA1)-14.4cM-P4HB-11.2cM-ETH3-4. 0cM-BMC1013. It was previously revealed that bovine Chr 19 contains the largest known conserved autosomal synteny among human, bovine, and mouse. This study has shown that gene orders within this segment are not conserved among the three species. We propose structural changes in an ancestral mammalian chromosome to account for these differences. This is the first interspecific hybrid backcross used in bovine linkage studies, and it has proven to be an effective tool for incorporating bovine type I loci into the linkage map even with the small sample size presently available. This resource will facilitate the generation of comparative linkage maps that address gene order and effectively predict the locations of unmapped loci across species.