Genetic variability of six indigenous goat breeds using major histocompatibility complex-associated microsatellite markers.

The present study aimed at analyzing the genetic variability of indigenous goat breeds (Capra hircus) using the MHC-associated microsatellite markers BF1, BM1818, BM1258, DYMS1, and SMHCC1. The following breeds were included: Chinese Xuhuai, Indian Changthangi and Pashmina, Kenyan Small East African (SEA) and Galla, and Albanian Vendi. To examine genetic variability, the levels of heterozigosity, degrees of inbreeding, and genetic differences among the breeds were analyzed. The mean number of alleles ranged from nine in the Galla to 14.5 in the Vendi breed. The mean observed heterozygosity and mean expected heterozygosity varied from 0.483 in the Vendi to 0.577 in the Galla breed, and from 0.767 in the SEA to 0.879 in the Vendi breed, respectively. Significant loss of heterozygosity (p < 0.01) indicated that these loci were not in Hardy-Weinberg equilibrium. The mean F(IS) values ranged from 0.3299 in the SEA to 0.4605 in the Vendi breed with a mean value of 0.3623 in all breeds (p < 0.001). Analysis of molecular variance indicated that 7.14% and 4.74% genetic variation existed among the different breeds and geographic groups, whereas 92.86% and 95.26% existed in the breeds and the geographic groups, respectively (p < 0.001). The microsatellite marker analysis disclosed a high degree of genetic polymorphism. Loss of heterozygosity could be due to genetic drift and endogamy. The genetic variation among populations and geographic groups does not indicate a correlation of genetic differences with geographic distance.

Expression of D-type cyclins in differentiating cells of the mouse spinal cord

The D-type cyclins form complexes with the cyclin dependent (CD) kinases CDK4 and CDK6 and promote the G1-S phase transition of the cell cycle by antagonizing the retinoblastoma suppresser protein pRB. In the developing nervous system D-type cyclins show spatially and temporally dynamic patterns of expression. We demonstrated that cyclin D1 was transiently expressed in differentiating spinal cord ventral interneurons while cyclin D3 protein was expressed in differentiating motor neurons and dorsal interneurons. This expression of cyclin D3 in neurons of the mantle zone was extended to all regions of the spinal cord at E15.5. The results suggest that cyclin D1 and D3 have specific functions in differentiating neurons. Similarly, in the developing midbrain-hindbrain region the D-type cyclins were expressed in different subsets of cells. Our results argue in favor of different functions for D-type cyclins during proliferation and differentiation of neural progenitors.