Abstract

A. E. Elkomy, Hanan H. Ghanem and Elsayed E. Hafez

Random population studies are very important to estimate the environmental factors in nutritional, physiological and breeding experiments. Studying the quantitative traits, consisting of genetic, environmental factors and interaction between them is very important as well. In a random population study, the genetic variation for 50 chicken individuals (Mandarah strain) of three successive generations was examined using differential display technique. The difference between the generations was measured by the change of DNA frequencies for the random population. Age at sexual maturity was changed during the three generations, but these differences were not significant. The body weight at sexual maturity (BWSM) of the 2nd and the 3rd generations was decreased significantly compared with the 1st generation. Whenever this decrease was not frequent, although, the egg number (EN), egg mass (EM) and rate of laying (RL) were not constant over generations, differences between the generations were highly significant for EN and EM only. In addition, comparative analysis based on the molecular levels and genotype stability clarified the genetic variations between the examined groups (females or males). Eleven bands with different molecular weights were observed in case of females in comparison to only 9 bands in case of the males. Phylogenetic studies revealed that, there was a genetic variability between females of the 1st generation. Furthermore, low level of similarity was observed between the 2nd generation in respect to the 1st and 3rd generations. Genetic similarity between females and males of the 2nd and the 3rd generations was 55%. It could be concluded that the differences in egg production trait, which was found among generations, may be due to indirect or natural selection.