The genetic component of mammalian male fertility is complex and involves
thousands of genes. The majority of these genes are distributed on autosomes and the X
chromosome, while a small number are located on the Y chromosome. Human and
mouse studies demonstrate that the most critical Y-linked male fertility genes are present
in multiple copies, show testis-specific expression and are different between species.
In the equine industry, where stallions are selected according to pedigrees and
athletic abilities but not for reproductive performance, reduced fertility of many breeding
stallions is a recognized problem. Therefore, the aim of the present research was to
acquire comprehensive information about the organization of the horse Y chromosome
(ECAY), identify Y-linked genes and investigate potential candidate genes regulating
stallion fertility.
To achieve theses goals, a direct cDNA (complementary DNA) selection
procedure was used to isolate Y-linked genes from horse testes and 29 Y-specific genes
were identified. All 29 genes were mapped to ECAY and their sequences were used to further expand the existing map. Copy number analysis identified 15 multicopy genes of
which 9 were novel transcripts. Gene expression analysis on a panel of selected body
tissues showed that some ECAY genes are expressed exclusively in testes while others
show ubiquitous or intermediate expression. Quantitative Real-Time PCR using primers
for 9 testis-specific multicopy genes revealed 5 genes with statistically significant
differential expression in testis of normal fertile stallions and stallions with impaired
fertility. Gene copy number analysis showed that the average copy number of 4 such
genes was decreased in subfertile/infertile stallions compared to normal animals.
Taken together, this research generated the first comprehensive physical gene
map for the horse Y chromosome and identified a number of candidate genes for stallion
fertility. The findings essentially expand our knowledge about Y chromosome genes in
horses, open a new avenue for investigating the potential role of ECAY genes in stallion
fertility which contribute to the development of molecular tools for the assessment of
fertility in stallions.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-08-7047 |
| Date | 2009 August 1900 |
| Creators | Paria, Nandina |
| Contributors | Raudsepp, Terje, Chowdhary, Bhanu P., Murphy, William J., Samollow, Paul B., Varner, Dickson D. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, thesis, text |
| Format | application/pdf |
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