Question

Write an essay on chromosomal aberrations, giving their cytological and genetic effects.

Answer 1

Chromosomal aberrations are structural changes in chromosomes resulting in alterations in gene number or sequence without changing chromosome number. They include deficiencies (deletions), duplications, translocations, and inversions. Cytologically, deletions show as loops or length differences during meiosis pairing, while translocations involve gene transfers between non-homologous chromosomes. Genetically, these aberrations disrupt gene balance, causing phenotypic abnormalities or lethality. For example, deletions remove genes, duplications increase gene dosage, translocations may cause sterility, and inversions rearrange gene order. Overall, chromosomal aberrations affect genetic stability, gene expression, and evolution, often producing visible phenotypic effects or genetic disorders.