Question

Heritable alteration in a cell/organism's phenotype (a product of gene expression) which is not attributable to changes in the nucleotide sequences of their DNA:

A) Mutation
B) Epigenetic modification
C) Transcriptional regulation
D) Codon substitution

Answer 1

Epigenetic modification is a heritable alteration in phenotype that is not caused by changes in DNA sequence. It can affect gene expression without changing the underlying genetic code.

Step-by-step explanation:

Epigenetic modification is a heritable alteration in a cell or organism's phenotype, which is not attributable to changes in the nucleotide sequences of their DNA. Unlike mutations, which involve changes in the DNA sequence, epigenetic modifications alter how genes are expressed without changing the underlying genetic code.

For example, DNA methylation and histone modification are two common epigenetic modifications that can affect gene expression. DNA methylation involves the addition of a methyl group to DNA, which can lead to the silencing or activation of genes. Histone modification involves chemical changes to the proteins called histones that DNA wraps around, which can also impact gene expression.