Question

Which of the following statements best describes alleles?

a) Two slightly different nucleotide sequences at different locations on homologous chromosomes

b) Two slightly different nucleotide sequences at the same location on homologous chromosomes

c) Two slightly different nucleotide sequences at the same location on non-homologous chromosomes

d) Two slightly different nucleotide sequences at different locations on non-homologous chromosomes

Answer 1

Alleles are slightly different nucleotide sequences at the same location on homologous chromosomes. They determine the variations of traits like blood type.

Step-by-step explanation:

An allele is a slightly different nucleotide sequence at the same location on homologous chromosomes.

For example, consider blood type. There are three possible gene sequences on the human chromosome that code for blood type: sequence A, sequence B, and sequence O. The blood type trait is determined by which two versions of the marker gene are inherited. It is possible to have two copies of the same gene sequence on both homologous chromosomes, with one on each (AA, BB, or OO), or two different sequences, such as AB.