Copy Number Variations Of Six Y-Link Genes In Water Buffalo

Recent transcriptomic analysis of the bovine Y chromosome revealed that at least six multi-copy protein coding gene families were located on the male-specific region of Y chromosome(MSY). Copy number variations(CNVs) of several MSY genes are closely related to male reproduction and spermatogenesis in cattle. However, the CNVs of MSY genes in water buffalo are unknown. Just the CNV of TSPY gene on water buffalo has been reported. The CNVs of TSPY、HSFY and PRAMEY were abundantly analyzed on human,cattle and mice. However, little is knew about CNVs of HSFY、ZNF280BY、SRY、DBY、UTY and OFD1 Y genes on water buffalo. Therefore, we aimed to investigate the CNVs of three genes(SRY, HSFY, and ZNF280BY) of 302 buffaloes from 19 breeds and other three genes(DBY, UTY and OFD1Y) of 105 buffaloes from six breeds of distributed in China, Vietnam and Laos using quantitative real-time PCR(qPCR). The main results are as follows:1. We firstly demonstrate that these six Y-link genes(HSFY、ZNF280BY、SRY、DBY、UTY and OFD1Y) expand differently on Y chromosome. The median copy number(MCN) of HSFY,ZNF280 BY and DBY genes were 48(ranging from 20 to 145), 257(ranging from 73 to 974),and 2(ranging from 1 to 4), respectively. The MCN of SRY and OFD1 Y were 1(ranging from1 to 4) which had CNVs in Vietnamese buffaloes. UTY gene shows one copy.2. This study indicates that HSFY and ZNF280 BY are multi-copy genes on the buffalo MSY.DBY, SRY, and OFD1 Y were low-copy number genes, while UTY was a single copy Y-linked gene on buffalo MSY.3. The MCN estimation between river buffalo and swamp buffalo showed no significant difference; the CNVs of HSFY, ZNF280 BY, SRY, DBY, UTY and OFD1 Y gene were not able to distinguish the Swamp buffalo from River buffalo. However, the MCNs estimation of HSFY and ZNF280 BY genes showed that there were differences between foreign buffalo(Vietnam and Laos) and Chinese buffalo.