Copy number variations of the extensively amplified Y-linked genes, HSFY and ZNF280BY, in cattle and their association with male reproductive traits in Holstein bulls

Xiang-Peng Yue,Chad Dechow,Wan-Sheng Liu,James Melton Dejarnette,Ti-Cheng Chang,Chu-Zhao Lei,Clifton Eugene Marshall

doi:10.1186/1471-2164-15-113

Abstract

BackgroundRecent transcriptomic analysis of the bovine Y chromosome revealed at least six multi-copy protein coding gene families, including TSPY, HSFY and ZNF280BY, on the male-specific region (MSY). Previous studies indicated that the copy number variations (CNVs) of the human and bovine TSPY were associated with male fertility in men and cattle. However, the relationship between CNVs of the bovine Y-linked HSFY and ZNF280BY gene families and bull fertility has not been investigated.ResultsWe investigated the copy number (CN) of the bovine HSFY and ZNF280BY in a total of 460 bulls from 15 breeds using a quantitative PCR approach. We observed CNVs for both gene families within and between cattle breeds. The median copy number (MCN) of HSFY among all bulls was 197, ranging from 21 to 308. The MCN of ZNF280BY was 236, varying from 28 to 380. Furthermore, bulls in the Bos taurus (BTA) lineage had a significantly higher MCN (202) of HSFY than bulls in the Bos indicus (BIN) lineage (178), while taurine bulls had a significantly lower MCN (231) of ZNF280BY than indicine bulls (284). In addition, the CN of ZNF280BY was positively correlated to that of HSFY on the BTAY. Association analysis revealed that the CNVs of both HSFY and ZNF280BY were correlated negatively with testis size, while positively with sire conception rate.ConclusionThe bovine HSFY and ZNF280BY gene families have extensively expanded on the Y chromosome during evolution. The CN of both gene families varies significantly among individuals and cattle breeds. These variations were associated with testis size and bull fertility in Holstein, suggesting that the CNVs of HSFY and ZNF280BY may serve as valuable makers for male fertility selection in cattle.

Highlights

Recent transcriptomic analysis of the bovine Y chromosome revealed at least six multi-copy protein coding gene families, including TSPY, HSFY and ZNF280BY, on the male-specific region (MSY)
The copy number (CN) of both gene families varies significantly among individuals and cattle breeds. These variations were associated with testis size and bull fertility in Holstein, suggesting that the copy number variations (CNVs) of HSFY and ZNF280BY may serve as valuable makers for male fertility selection in cattle
The objective of this study is to determine whether the bovine HSFY and ZNF280BY have any CNVs among individuals and breeds, and if their CNVs are associated with bull reproductive traits

Summary

Introduction

Recent transcriptomic analysis of the bovine Y chromosome revealed at least six multi-copy protein coding gene families, including TSPY, HSFY and ZNF280BY, on the male-specific region (MSY). Recent progress on sequencing of the mammalian Y chromosomes has revealed that the amplification of the malespecific region on the Y (MSY) is a unique phenomenon during the mammalian sex chromosome evolution [1,2,3] Because this amplification process was lineage-dependent, number of studies have demonstrated that Y-linked CNVs are associated with male fertility in humans [9,10] and cattle [11,12]. There are at least six multi-copy protein-coding gene families on BTAY, including TSPY (testis-specific protein, Y-encoded), HSFY (heat-shock transcription factor, Y-linked), PRAMEY (preferentially expressed antigen in melanoma, Y-linked), ZNF280AY (zinc finger protein 280A, Y-linked), ZNF280BY (zinc finger protein 280B, Y-linked) and EGLY (envelope glycoprotein like, Y-linked) [2]. Yue et al [12] has recently identified that the CNV of the bovine PRAMEY was negatively associated with testis size, non-return rate and percentage of normal sperm

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