Chromosome characterisation of malabari goats and its crosses in Kerala

Abstract

The chromosome profile of goats was studied with a view to find its number, to prepare the karyotypes of female and male goats of the Malabari and its crosses with Saanen and Alpine and to assess its morphometric values. The experiments were carried out in jugular blood lymphocytes. The cultures were prepared using RPMI 1640 as the medium. The comparative efficacy of different mitogens viz. PHA, PWM and their combination, with different incubation time, revealed that the combination of PHA and PWM at an incubation period of 70.5 h yielded the optimum results. The diploid number of chromosomes in all the genetic groups of goats were found to be 60. Autosomes as well as X chromosomes were found to be acrocentric. The X chromosome was quite prominent in being the longest of all. The Y chromosome was the shortest and the only metacentric in the complement. In karyotypes of the three genetic groups, it was observed that twenty-nine homologous pairs of autosome formed a closely graded seriation. Sexual dimorphism was exhibited with an unequal pair of X and Y chromosomes in males and an equal pair of X chromosomes in the females. The relative length was estimated for each pair of chromosomes in percentage. The X chromosome contributed to more than five per cent of the total complement length in all the three genetic groups. In Malabari, Saanen x Malabari and Alpine x Malabari, the relative length of the Y chromosomes were 1.552+0.10,1.321+0.09 and 1.548+0.10 respectively. The analysis of variance of relative length of X chromosomes revealed a significant difference among the three genetic groups.