Question

Continuous variation are due to

• A. Chromosomal aberrations
• B. Polyploidy
• C. Mutation
• D. Crossing over

Answer 1

The correct option is D Crossing over

Continuous variations are the one that shows the whole range of variations in the character; it is not expressed by two extremes but the whole range. Continuous traits are controlled by more than one genes, each gene has two to several alleles which impart a great degree of variations to the trait. Further, cross over during prophase I of meiosis generates new allelic combinations; thus imparting a wide range of phenotype to the trait. Chromosomal aberrations are the structural or numerical changes in chromosomes; it includes inversion, duplication, deletion and translocation. The presence of multiples of complete haploid chromosomal sets is called as polyploidy. Mutation is the change in chemical structure of the gene. Chromosomal aberration, polyploidy, and mutation do not produce new allelic combinations for a gene; they produce discrete variations, not the continuous variations. The correct answer is D.