Genomic detection of lethal recessive alleles by absence or lower frequency homozygous haplotypes in zebu cattle

• Grant number: 13/23673-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): January 25, 2014
• Effective date (End): January 24, 2015
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Humberto Tonhati
• Grantee: Daniel Jordan de Abreu Santos
• Supervisor: Johann Sölkner
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Research place: Universität für Bodenkultur Wien, Austria
• Associated to the scholarship: 11/10386-8 - Genomic studies related to milk, fat and protein yields in guzerat cattle, BP.DR

Abstract

In view of advances in Brazilian livestock research and knowing that fertility is an important and complex trait to be improved, this project aims to detect genes possibly related to embryonic death; an important indicator of fertility. Traditionally, the approach taken was to monitor the development of the embryo and record abortions, stillbirths and any other losses. The cost of production for cattle increases drastically as fertility declines due, to the need to undertake multiple insemination or repeated natural mating. However with the availability of single nucleotide polymorphism (SNP); different approaches have been proposed as alternative ways of detecting these lethal haplotypes. These new ways of identifying the haplotypes in the genome have been used by VanRaden et al (2011), Sonstegard et al (2013) and Fritz et. al (2013) to find interesting lethal haplotypes present in dairy cattle breeds. To affirm that these identified haplotypes were indeed responsible for embryonic mortality; Sontegard et al. (2013) undertook a study using sequence data after identifying the haplotypic region and were able to confirm. The approach as proposed by Vanraden et al (2011) is to search through the genome and identify haplotypes that are never present or in very low frequency in their homozygote state, although they were expected to be in high frequency due to excessive use of the ancestors carrying these haplotype. In short it is to indent haplotypes that are never observed in its homozygosite states although the sires/ancestors carrying them have been used to produce hundreds and thousands of offsprings. Therefore, this study aims at identifying these lethal haplotypes in two (2) Zebuine cattle breeds for genetic diseases that hitherto were not observed, it will also be the first study to be undertake in Bos indicus cattle breeds. (AU)