Genes and Phenotypic Expression: Cellular Differentiation and Epigenetics

Cellular Differentiation

Different cell types in the body have varying structures suited to their specific functions.

Stem Cells

Undifferentiated cells with the potential to become any cell type.

Gene Activation

Specialization depends on which genes are activated or deactivated.

Epigenetic Factors

Changes during a parent cell's lifetime passed to daughter cells via cell division; daughter cells inherit the same silenced or switched-on genes.

Methylation

Genes can be 'locked off' via the addition of a methyl group (CH_3) to cytosine nucleotides.

Histone Modification

Chemical changes to histone proteins, including methylation, acetylation, phosphorylation, and ubiquitination.

Epigenetics

Heritable changes in gene expression.

Cancer

Can result from uncontrolled cell division if tumor suppressor genes become methylated.

Fragile X Syndrome

Methylation of cytosine in CGG repeats in the FMR1 gene, preventing production of a protein needed for normal protein development.

Depends on factors controlling transcription and translation. Changes in DNA methylation and histone modification can alter gene expression, affecting phenotypic expression. Epigenetic modifications in genes controlling cell