question_answer 26)

  Mendel's law of independent assortment holds good for genes situated on the (a) non-homologous chromosomes                        (b) homologous chromosomes (c) extra nuclear genetic element                             (d) same chromosome

Answer:

                    (a)Non-homologous Chromosome The law of independent assortment holds true as long as two different genes are on separate chromosomes. When the genes are on separate chromosome, the two alleles of one gene (A and a) will segregate into gametes independently of the two alleles of the other gene (B and b). Equal numbers of four different gametes will form AB, aB, Ab, ab. But if the two genes are on the same chromosome, then they will be linked and will segregate together during meiosis, producing only two kinds of gametes.   Homologous chromosomes are similar but not identical. Each carries the same gene insame order but the alleles for each trait may not be the same. Extra nuclear genetic elements are also called as plasmids and shows the pattern of maternal inheritance.