Extensive nonhomologous meiotic synapsis between normal chromosome axes of an rcp(3;6)(p14;q21) translocation in a hairless Mexican boar

Due to its low fertility, expressed as small litter size, a Mexican hairless boar was subjected to cytogenetic investigation. Analysis of G-banded mitotic chromosomes revealed a reciprocal chromosome translocation, rcp(3;6) (p14;q21). Synaptonemal complex analysis showed a regular pairing behavior of the translocation chromosome axes, always resulting in a quadrivalent configuration. However, due to extensive nonhomologous pairing between the axes of nonderivative chromosomes 3 and 6, the quadrivalent mostly had an asymmetrical cross-shaped morphology. The nonhomologous pairing occurred not only at mid and late pachytene, but also at the earliest stage of pachytene. It seems that early pachytene heterosynapsis is a common phenomenon in the pairing behavior of pig reciprocal translocations. Therefore, heterosynapsis may reduce apoptosis of germ cells due to partial absence of homologous synapsis during the pairing phase of meiosis. The frequency of spermatocytes showing quadrivalent configurations with unpaired axial segments apparently did not affect germ cell progression in the boar, since fairly normal testicular histology was noticed. Copyright � 2008 S. Karger AG

Population structure and paternal admixture landscape on present-day Mexican-mestizos revealed by Y-STR haplotypes

The purpose of this study was to identify genotype variants in the beta-casein (CSN2) and kappa-case (CSN3) genes using the PCR-RFLP method in a population of 202 Holstein cattle from two highly technified farms in the state of Jalisco, Mexico. We further assessed the association of these variants with milk production during a second lactation period. In the first population (n = 102), the genotypic frequencies for CSN2 were A1 = 0.387 and A2 = 0.613, while for CSN3, they were A = 0.829 and B = 0.172. In the second population (n = 100), the genotypic frequencies for CSN2 were A1 = 0.430 and A2 = 0.570, while for CSN3, they were A = 0.795 and B = 0.205. No differences in frequency distribution were noted in either population, and both genes were in Hardy-Weinberg equilibrium. There was greater genetic diversity for the CSN2 gene (0.477 and 0.493) than for the CSN3 gene (0.286 and 0.328) in both populations, with no significant differences between them. The fixation index was low for both genes, suggesting that there was no significant decrease in heterozygosity. The same genetic changes occur in both genes, and give their high similarity index (0.99 and 0.99). The statistical association analysis between genotypes of both genes and milk production revealed there were no significant differences between populations. Furthermore, no significant additive or dominant effects of both casein genes on milk production were identified within our population samples. " 2014, Pakistan Agricultural Scientists Forum. All rights reserved.",,,,,,,,,"http://hdl.handle.net/20.500.12104/43724","http://www.scopus.com/inward/record.url?eid=2-s2.0-84908335020&partnerID=40&md5=d902406f03d7d2354c7683ac6de6a803",,,,,,"5",,"Journal of Animal and Plant Sciences",,"131

Polymorphisms in beta and kappa-casein are not associated with milk production in two highly technified populations of holstein cattle in Mexico

The purpose of this study was to identify genotype variants in the beta-casein (CSN2) and kappa-case (CSN3) genes using the PCR-RFLP method in a population of 202 Holstein cattle from two highly technified farms in the state of Jalisco, Mexico. We further assessed the association of these variants with milk production during a second lactation period. In the first population (n = 102), the genotypic frequencies for CSN2 were A1 = 0.387 and A2 = 0.613, while for CSN3, they were A = 0.829 and B = 0.172. In the second population (n = 100), the genotypic frequencies for CSN2 were A1 = 0.430 and A2 = 0.570, while for CSN3, they were A = 0.795 and B = 0.205. No differences in frequency distribution were noted in either population, and both genes were in Hardy-Weinberg equilibrium. There was greater genetic diversity for the CSN2 gene (0.477 and 0.493) than for the CSN3 gene (0.286 and 0.328) in both populations, with no significant differences between them. The fixation index was low for both genes, suggesting that there was no significant decrease in heterozygosity. The same genetic changes occur in both genes, and give their high similarity index (0.99 and 0.99). The statistical association analysis between genotypes of both genes and milk production revealed there were no significant differences between populations. Furthermore, no significant additive or dominant effects of both casein genes on milk production were identified within our population samples. © 2014, Pakistan Agricultural Scientists Forum. All rights reserved