Detection of Chromosome Segments of Zebu and Taurine Origin and Their Effect on Body Weight

Introduction Taurine (Bos taurus) and zebu (Bos indicus) cattle were domesticated independently in the Near East and in India respectively (Beja-Pereira et al., 2006) and are believed to have diverged 117-275,000 years ago (Bradley et al., 2006). Bos taurus cattle were introduced to Australia by European settlers in the end of the 18th century. The main B. indicus breed used for beef production in Australia is the Brahman which was imported in the 20 th century. The Brahman breed originated in the United States of America in the early 1900s where it was developed from progeny of four Indian cattle breeds with some infusion of British-bred cattle (http://www.brahman.com.au/history.html). Since then crossbreeding between Brahman and B. taurus breeds has been used to form several composite breeds such as the Santa Gertrudis. Because this crossbreeding has been recent, large chromosome segments of either B. taurus or B. indicus origin should be segregating in these composite breeds.