Polymorphism of locus DRB3.2 in populations of Creole Cattle from Northern Mexico

The polymorphism of locus BoLA-DRB3.2 of the Major Histocompatibility Complex was evaluated in two northern Mexican Creole cattle populations, Chihuahua (n = 47) and Tamaulipas (n = 51). The BoLA-DRB3.2 locus was typed by amplification and digestion with restriction endonuclease enzymes (PCR-RFLP). Fifty-two alleles were detected (28 previously reported and 24 new ones). In the Chihuahua population, 18 alleles and 5.5 effective alleles were found, while in the Tamaulipas population there were 34 and 10.8, respectively. The allele frequencies ranged from 0.011 to 0.383 in Chihuahua and from 0.010 to 0.206 in Tamaulipas. The frequencies of the new alleles in both cattle populations were low (0.010 to 0.053). The expected heterozygosity was 0.827 and 0.916, respectively, for the Chihuahua and Tamaulipas populations. Both populations presented a heterozygote deficit: [Chihuahua FIS = 0.1 (p = 0.019) and Tamaulipas FIS = 0.317 (p < 0.001)]. In conclusion, this study showed that the Mexican Creole cattle have many low-frequency alleles, several of which are exclusive to these populations. Genetic distances obtained show that the Mexican Creole cattle population is composed of independent populations, far apart from other South American Creole populations.

Genetic polymorphism of the alpha s1-casein locus in five populations of goats from Mexico

With the objective of estimating allele frequencies, and testing for population divergence for the CSN1S1 locus, genotypes of animals from five goat populations; Saanen (n = 97), Alpine (n = 81) Toggenburg (n = 92), local goats with external appearance similar to the Murciana-Granadina breed from Central Mexico (n = 26) and heterogeneous local animals denominated Mosaico Lagunero (n = 30), from Northern Mexico, were identified using PCR and Xmn1 PCR-RFLP methodology. For Saanen, Alpine and Toggenburg, the sum of E and F alleles had the largest frequencies (from 0.468 to 0.789), while for the groups local Murciana-Granadina and Mosaico Lagunero the sum of the most frequent allelic groups (A and B), were 0.385 and 0.533 respectively. Both local Murciana-Granadina and Mosaico Lagunero populations showed heterozygote excess (P < 0.08). The percentage of the total genetic variation (F ST) explained by population differences was 5.16. There was genetic differentiation for most pair comparisons between populations (P < 0.05), excepting for Alpine versus Toggenburg, and Toggenburg versus Mosaico Lagunero (P > 0.05). For Saanen and Alpine the frequencies of alleles E and F were similar to the same breeds previously analyzed in Europe. Therefore there are opportunities of increasing the frequency of the strong alleles for protein content Gene Assisted Selection (GAS) in these two breeds. For Toggenburg the most frequent allelic groups were F (0.32) and B (0.21). Results indicate differentiation between most populations for this locus. Moreover, heterozygote excess in local populations indicated breed admixture.