Identification of crossbred buffalo genotypes and their chromosome segregation patterns

Abstract

Chromosome analysis on different breed types of water buffaloes (Bubalus bubalis) was undertaken to identify their karyotypes and to determine the pattern of chromosome segregation in crossbred water buffaloes. Altogether, 75 purebred and 198 crossbred buffaloes including 118 from Malaysia and 80 from the Philippines, were analyzed in this study. The diploid chromosome number of the swamp buffalo from both countries was 48 and that of the river buffalo was 50, while all F1 hybrids exhibited 49 chromosomes. The F2 hybrids consisted of three different karyotype categories (2n = 48, 2n = 49, and 2n = 50), whereas the backcrosses included two different karyotype categories each, with 2n = 48 and 2n = 49 in the three quarters swamp types and 2n = 49 and 2n = 50 in the three quarters river types. Chi-square tests on pooled data from Malaysia and the Philippines indicated that the distribution of different karyotype categories of F2 animals did not deviate significantly from the 1:2:1 ratio expected if only balanced gametes with 24 and 25 chromosomes were produced by the F1 hybrids. In the three quarters swamp and three quarters river types, the respective karyotypic categories were in ratios approximating 1:1. The distribution of chromosome categories among the F2 hybrids and backcrosses suggests that only genetically balanced gametes of the F1 hybrids are capable of producing viable F2 and backcross generations.

Mitochondrial DNA analyses of Indian water buffalo support a distinct genetic origin of river and swamp buffalo

“…Cytogenetic (Harisah et al. 1989), ecological and phenotypic parameters (Cockrill 1981); cytochrome b sequences (Amano et al.…”

Genome-wide analysis reveals genetic diversity, linkage disequilibrium, and selection for milk traits in Chinese buffalo breeds

“…To date, Chinese swamp buffaloes have been classed into 24 local types based mainly on the regional distribution [2]. To improve the milk and meat performance of swamp buffalo, crossbred buffalo by hybridizing the river-type bulls with swamp-type cows has been practiced in many Asian countries, and they are fertile, although the hybrid may have a lower reproductive value [3, 4]. The cross-breeding programs in China began in the 1950s by introducing the exotic river breeds such as Murrah and Nili-Ravi, which has resulted in the different crossbred breeds including the Murrah × local buffalo, Nili-Ravi × indigenous buffalo, and Murrah × Nili-Ravi × indigenous buffalo.…”

Embryo Sexing and Sex Chromosomal Chimerism Analysis by Loop-Mediated Isothermal Amplification in Cattle and Water Buffaloes

“…We identified partial sequences of a BRY.2 homologue in swamp and river buffaloes that originated in regions different from BuRY.I and designated them sBuRY.2 and rBuRY.2, respectively [40]. BuRY.2 was highly conserved between swamp and river buffaloes, despite the fact that these species have different karyotypes (swamp type, 2n=48; river type, 2n=50) and have significant genetic differentiation [41, 42]. Therefore, the authors inferred that BRY-like sequences in the family Bovidae have remained stable.…”