Search for polymorphisms through next- generation sequencing of genes involved in reproductive development in Guzerat bulls

FERNANDEZ M E; CUNHA CARDOSO D; GIOVAMBATTISTA G; LOAIZA ECHEVERI A M; GOSZCZYNSKI D E; HENRY M R J M; LIRON J P; DRUMMOND M; PERAL GARCIA P; ANDRADE DE OLIVEIRA D.A.

UTAH

Conferencia; 35th International Society for Animal Genetics Conference; 2016

Reproductive development is regulated by genetic and environmental factors. Among reproductive characters, puberty is an important factor in cattle breeding, and strong differences exist between the age ofarrival to puberty between and within breeds. Guzerat is one of the most important zebuine breeds raised in South American tropical regions for meat production, but unfortunately, it possess several reproductive dis-advantages when compared with European breeds, including later age at puberty. The identification of genes and polymorphisms explaining the variation in this character could be useful in the early selection ofprecocious bulls, increasing the genetic progress in the improvement programs of this breed. The objective of this work was to detect polymorphisms in genes associated to sexual development in Guzerat bulls. To do this, 690 amplicons belonging to coding, promoter and regulating (5 ́UTR y 3 ́UTR) regions in 72 genes were sequenced in 96 males through next-generation sequencing technology using MiSeq sequencer (Illumina Inc.). First, raw data was filtered by sequence quality. Subsequently, sequences were aligned to the reference Bos taurus genome, and detection and geno-typing of SNP and indels were performed. From the total polymorphisms detected in the approximately 300,000 bp sequenced, and after applying alignment quality filter and minimun allele frequency filter of0.05, 798 SNPs (one every 375 bp) and 39 insertions and 35 deletions were obtained. The latter belong to one indel every approximately 4000 pb; however, these results should be studied deeply, as some of them could be artifacts. Using a program for predicting the effects of different types of variants, polymorphisms were classify by genomic location, type,functional class (50.4% missense, 1.5% nonsense and 48.1% silent) and impact on the future protein (high, low or moderate). Furthermore, some of them are novel SNPs, because they were not previously reported. A continuation of this work, the effects of the detected variants, will be studied in detail, and association of these polymorphisms with age at puberty estimated through scrotal circumference and sperm motility in the studied breed will be analyzed. The results obtained will contribute to the understanding of genetic regulation of puberty.