Candidate Genes Associated with Testicular Development, Sperm Quality, and Hormone Levels of Inhibin, Luteinizing Hormone, and Insulin-Like Growth Factor 1 in Brahman Bulls

• Published in: Biology of reproduction Vol. 87; no. 3; p. 58
• Main Authors: FORTES, Marina R. S, REVERTER, Antonio, HAWKEN, Rachel J, BOLORMAA, Sunduimijid, LEHNERT, Sigrid A
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01-09-2012
• Subjects: Animals; Biological and medical sciences; Cattle - blood; Cattle - genetics; Cattle - growth & development; Cattle - physiology; Fundamental and applied biological sciences. Psychology; Genetic Association Studies; Genome-Wide Association Study; Genotype; Growth and Development - genetics; Inhibins - analysis; Inhibins - blood; Inhibins - genetics; Insulin-Like Growth Factor I - analysis; Insulin-Like Growth Factor I - genetics; Insulin-Like Growth Factor I - metabolism; Luteinizing Hormone - analysis; Luteinizing Hormone - blood; Luteinizing Hormone - genetics; Male; Osmolar Concentration; Polymorphism, Single Nucleotide; Quantitative Trait Loci - physiology; Semen Analysis - veterinary; Testis - growth & development; Testis - metabolism; Vertebrates: reproduction; Spermatozoa; Inhibin; Ox; Male; male fertility; Germinal cell; Reproduction; Fertility; Quality; Development; Luteinizing hormone; Candidate gene; Testicular hormone; Ungulata; Puberty; Gonadotropin; Insulin like growth factor 1; reproductive hormones; Vertebrata; Mammalia; Adenohypophyseal hormone; Animal; bovine; Artiodactyla; genome-wide association; Genome
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod.112.101089

Bull fertility is an important target for genetic improvement, and early prediction using genetic markers is therefore a goal for livestock breeding. We performed genome-wide association studies to identify genes associated with fertility traits measured in young bulls. Data from 1118 Brahman bulls were collected for six traits: blood hormone levels of inhibin (IN) at 4 mo, luteinizing hormone (LH) following a gonadotropin-releasing hormone challenge at 4 mo, and insulin-like growth factor 1 (IGF1) at 6 mo, scrotal circumference (SC) at 12 mo, ability to produce sperm (Sperm) at 18 mo, and percentage of normal sperm (PNS) at 24 mo. All the bulls were genotyped with the BovineSNP50 chip. Sires and dams of the bull population (n = 304) were genotyped with the high-density chip (∼800 000 polymorphisms) to allow for imputation, thereby contributing detail on genome regions of interest. Polymorphism associations were discovered for all traits, except for Sperm. Chromosome 2 harbored polymorphisms associated with IN. For LH, associated polymorphisms were located in five different chromosomes. A region of chromosome 14 contained polymorphisms associated with IGF1 and SC. Regions of the X chromosome showed associations with SC and PNS. Associated polymorphisms yielded candidate genes in chromosomes 2, 14, and X. These findings will contribute to the development of genetic markers to help select cattle with improved fertility and will lead to better annotation of gene function in the context of reproductive biology.