Genetic variation analysis of cytb gene of cattle bred in Iraq

Abstract

The present study was conducted at laboratory of Genetic Engineering at the University of Basrah  from 01/04/2017 to 01/08/2018. The aim of  study was identify genetic variations and SNPs in mtDNAcytb; among Holstein, Local Iraqi cattle and their crosses. The primer used in this study amplified 1139-bp fragments from cytb gene. The results showed the presence of 3, 12 and 2 polymorphic sites leading to the construction of 3different haplotypes for Holstein, local and crosses respectively. Haplotype and nucleotide diversity were (0.275; 0.00047), (0.417, 0.00068), and (0.733, 0.00686) respectively.  Neighbor-joining trees were constructed using 34 samples showed that all studied cattle appeared into haplotype 1(H1), while Holstein also appeared in H5 and H6 (with different two or one bases respectively). Local breed included in H2 and H3 (with one different base), the crosses in H4(with 11 different bases). AMOVA showed that variation within breed (between individuals was higher (65.35%) than between breeds (34.65%). Neutrality test both Tajima's D and Fu’s Fs revealed that Holstein recorded the highest negative values (-1.67053 and -0.24213 respectively). Whereas, the crosses cattle recorded positive values (1.31709 and 6.05664 respectively). The local breed showed positive and negative values near to zero (-0.93613 and 0.01635 respectively). It can be concluded from these results that Iraqi local breeds showed high genetic variability and totally differ from other breeds in the world.