Genome-wide association study identifies genomic regions associated with key reproductive traits in Korean Hanwoo cows

Background Conducting genome-wide association studies (GWAS) for
reproductive traits in Hanwoo cattle, including age at first calving
(AFC), calving interval (CI), gestation length (GL), and number of
artificial inseminations per conception (NAIPC), is of paramount
significance. These analyses provided a thorough exploration of the
genetic basis of these traits, facilitating the identification of key
markers for targeted trait improvement. Breeders can optimize their
selection strategies, leading to more efficient and sustainable breeding
programs, by incorporating genetic insights. This impact extends beyond
individual traits and contributes to the overall productivity and
profitability of the Hanwoo beef cattle industry. Ultimately, GWAS is
essential in ensuring the long-term genetic resilience and adaptability of
Hanwoo cattle populations. The primary goal of this study was to identify
significant single nucleotide polymorphisms (SNPs) or quantitative trait
loci (QTLs) associated with the studied reproductive traits and
subsequently map the underlying genes that hold promise for trait
improvement. Results A genome-wide association study of reproductive
traits identified 68 significant single nucleotide polymorphisms (SNPs)
distributed across 29 Bos taurus autosomes (BTA). Among them,
BTA14 exhibited the highest number of identified SNPs (25), whereas BTA6,
BTA7, BTA8, BTA10, BTA13, BTA17, and BTA20 exhibited 8, 5, 5, 3, 8, 2, and
12 significant SNPs, respectively. Annotation of candidate genes within a
500 kb region surrounding the significant SNPs led to the identification
of ten candidate genes relevant to age at first calving. These genes were:
FANCG, UNC13B, TESK1, TLN1, and CREB3 on BTA8; FAM110B, UBXN2B, SDCBP, and
TOX on BTA14; and MAP3K1 on BTA20. Additionally, APBA3, TCF12, and ZFR2,
located on BTA7 and BTA10, were associated with the calving interval;
PAX1, SGCD, and HAND1, located on BTA7 and BTA13, were linked to gestation
length; and RBM47, UBE2K, and GPX8, located on BTA6 and BTA20, were linked
to the number of artificial inseminations per conception in Hanwoo cows.
Conclusions The findings of this study enhance our knowledge of the
genetic factors that influence reproductive traits in Hanwoo cattle
populations and provide a foundation for future breeding strategies
focused on improving desirable traits in beef cattle. This research offers
new evidence and insights into the genetic variants and genome regions
associated with reproductive traits and contributes valuable information
to guide future efforts in cattle breeding.