Association of genetic variants of beta-lactoglobulin gene with milk production in a herd and a superior family of Holstein cattle

Polymorphism of the beta-lactoglobulin [beta-LG] gene in 101 cows belonging to the Holstein herd and a superior cow, producing more than 150 Kg milk/day, together with four offsprings was investigated by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism [PCR-RFLP] method. In the Holstein herd, the alleles A and B of the beta-LG gene had frequencies of 0.53 and 0.47, respectively. The genotypes AA, AB and BB of the beta-LG gene were estimated to have frequencies of 0.257, 0.544 and 0.198, respectively. Genotypes were distributed according to the Hardy-Weinberg equilibrium. Results indicated that the beta-LG genotypes significantly affected [P< 0.01] milk yield [genotype AA being more effective than genotype BB]. The superior cow and her progenies were all heterozygotes [AB]

Evaluation of genetic variability in a breeder flock of native chicken based on randomly amplified polymorphic DNA markers

A study was undertaken to evaluate the genetic variation in the 10[th] generation of a breeder flock of native breed selected for high egg and meat production in native fowls breeding station, Mazandaran, Iran. Venous blood samples were collected from 100 birds of both sexes. The RAPD-PCR technique was applied to generate a DNA fingerprint of individuals. Initially, a total of 20 ten-nucleotide arbitrary primers were used but 14 of 20 primers revealed a pattern with scorable amplified bands. From a total number of 140 scored bands 63 [45%] and 77 [55%] were described as polymorphic and monophormic respectively. The average number of bands per primer varied from 4 to 16 and with sizes varying from 200 to 2100 bp in length. The estimated band sharing frequency varied from 0.79 to 0.96 between individuals. The average genetic similarity and genetic variance between individuals within the population were 0.89 and 0.11, respectively. The existence of high levels of polymorphism after 10th generation of selection may indicate the accuracy of used the selection program and also the large enough effective population size in this breeding flock. It could be concluded that RAPD markers are effective in detecting genetic similarities and genetic variances among individuals in poultry breeder flocks