Question

5. (16 pts.) A cell has two pairs of submetacentric chromosomes, which we wili cail chromosomes I,, Ib, Ila, and Ilb. Submetacentric chromosomes have their centro nere abou midway between the telomere and middle of the chromosome as shown. Chromosomes Ia and I, are homologues and chromosomes II, and Ilb are homologues. Allele R is located on the p arm (short arm) of chromosome of chromosome la, and allele r is located at the same position on chromosome lb. Allele G is located on the long arm (q arm) of chromosome la and allele g is located at the same position on chromosome I,. Allele N is located on the q arm of chromosome II, and allele n is located at the same position of chromosome llb Draw these chromosomes, identifying genes R, r, G, g, N, and n as they might appear in metaphase I of meiosis. Assume there is no crossing over. a. Taking independent assortment and the subsequent random separation of chromosomes in anaphase I, draw the chromosomes, with genes identified, present in all possible gametes that could result once this cell completes meiosis. As above, assume there is no crossing over Explain in your own words what is meant by independent assortment. b.

Answer 1

In meta phase I of meosis the chromosomes would align themselves in the equitorial plane the homologous pairs R r, Gg and N n coming together. They would prepare for haploid division by extending the chromosomal arm for chiasmata formation.