Which of the following does not control gene expression?Group of answer choicesChromatin structureNumber of genesDNA methylationHistone modificationHMG protein

To determine which of the options does not control gene expression, we will evaluate each one:

1. Chromatin structure: Chromatin structure plays a crucial role in gene expression regulation. It can affect the accessibility of genes to transcription factors and other regulatory proteins. Therefore, chromatin structure does control gene expression.

2. Number of genes: The number of genes in an organism's genome does not directly control gene expression. However, the presence or absence of specific genes can influence gene expression patterns.

3. DNA methylation: DNA methylation is an epigenetic modification that can regulate gene expression. Methylation of certain regions of DNA can lead to gene silencing or reduced expression. Therefore, DNA methylation does control gene expression.

4. Histone modification: Histone modification refers to chemical changes that occur on histone proteins, which are involved in DNA packaging. These modifications can affect the accessibility of genes and regulate gene expression. Therefore, histone modification does control gene expression.

5. HMG protein: High Mobility Group (HMG) proteins are a family of proteins that can bind to DNA and influence chromatin structure. They can act as architectural factors and affect gene expression. Therefore, HMG protein does control gene expression.

Based on the above analysis, the option that does not control gene expression is the "Number of genes."