Journal Article

A Gene Catalogue of the Euchromatic Male-Specific Region of the Horse Y Chromosome: Comparison with Human and Other Mammals

Pearks Wilkerson, Alison J., O'Brien, Patricia C. M., Chowdhary, Bhanu P., Ferguson-Smith, Malcom A., Love, Charles C., Paria, Nandina, Raudsepp, Terje, Murphy, William J., Rakestraw, Peter, Arnold, Carolyn

2011

Overview

Studies of the Y chromosome in primates, rodents and carnivores provide compelling evidence that the male specific region of Y (MSY) contains functional genes, many of which have specialized roles in spermatogenesis and male-fertility. Little similarity, however, has been found between the gene content and sequence of MSY in different species. This hinders the discovery of species-specific male fertility genes and limits our understanding about MSY evolution in mammals. Here, a detailed MSY gene catalogue was developed for the horse--an odd-toed ungulate. Using direct cDNA selection from horse testis, and sequence analysis of Y-specific BAC clones, 37 horse MSY genes/transcripts were identified. The genes were mapped to the MSY BAC contig map, characterized for copy number, analyzed for transcriptional profiles by RT-PCR, examined for the presence of ORFs, and compared to other mammalian orthologs. We demonstrate that the horse MSY harbors 20 X-degenerate genes with known orthologs in other eutherian species. The remaining 17 genes are acquired or novel and have so far been identified only in the horse or donkey Y chromosomes. Notably, 3 transcripts were found in the heterochromatic part of the Y. We show that despite substantial differences between the sequence, gene content and organization of horse and other mammalian Y chromosomes, the functions of MSY genes are predominantly related to testis and spermatogenesis. Altogether, 10 multicopy genes with testis-specific expression were identified in the horse MSY, and considered likely candidate genes for stallion fertility. The findings establish an important foundation for the study of Y-linked genetic factors governing fertility in stallions, and improve our knowledge about the evolutionary processes that have shaped Y chromosomes in different mammalian lineages.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Analysis / Animals / Antigens / Bacterial artificial chromosomes / Biological evolution / Biology / Carnivores / Cats / Cattle / Chromosomes / Contig Mapping / Copy number / DNA, Complementary - genetics / Euchromatin - genetics / Evolution (Biology) / Evolution, Molecular / Evolutionary genetics / Female / Fertility / Fertility - genetics / Gene Dosage - genetics / Gene expression / Genes / Genetic factors / Genetic research / Genomes / Genomics / Horses / Horses - genetics / Horses - physiology / Humans / Laboratories / Male / Males / Mammals / Mice / Mitochondrial DNA / Molecular biology / Nandina / Open Reading Frames - genetics / Polymerase chain reaction / Primates / RNA, Messenger - genetics / Rodents / Sex Characteristics / Species / Spermatogenesis / Testes / Testis - metabolism / Transcription / X Chromosome - genetics / Y Chromosome - genetics / Y Chromosomes