Indicate whether the following statements are true or false

Indicate whether the following statements are true or false and briefly explain your reasoning. i. All genes are made of DNA and code for proteins. ii. By definition, mutant alleles are recessive and wild-type alleles are dominant. iii. New alleles at a locus arise by changes in DNA sequence (i.e., mutations). iv. In a population of individuals, there can be more than two different types of alleles for the same gene.

Solution

1. all genes are made of DNA and code for proteins- true

A gene means any part of DNA that encodes for proteins. all the genes are of DNA. but not all the DNA are genes. . the DNA transcribes into RNA, where the intron molecules are spliced and exon part codes for proteins.

2. mutant alleles are recessive and wild type alleles are dominant alleles- true

wild type alleles encode for a product and express themselves. recessive alleles are not expressed in the presence of wild type alleles.

3. new alleles arise by mutations- true

mutations are the major source of formation of new alleles.

4. there can be more than two different types of alleles for the same gene- true.

best example is blood groups (multiple alleles). A allele indicates A-antigen and corresponds to A-blood group

B allele indicates B-antigen and corresponds to B-blood group.

i allele indicates no antigen and corresponds to O-blood groups.