Question

Write about the role of chromosomal aberrations in evolution.

Answer 1

During the process of meiosis, one or more chromosomes may break. Such broken fragments of chromosomes may be subjected to several modified organisations, such as deletion, translocation, inversion, duplication.
All these changes may alter the genomes of gametes. Sometimes a pair of homologous chromosomes may fail to separate in meiosis. It will result in gametes with one chromosome less or one chromosome more than normal. The progeny formed from such gametes is called polysomic. It will have fewer or more chromosomes than normal. In certain cases, the whole set of homologous chromosomes does not separate in meiosis. It results in diploid gametes. Fusion of such gametes with a normal haploid gamete gives rise to progeny with a triploid chromosome number. This condition is called polyploidy. It is more vigorous. Such forms can give rise to new species and cause variation.