1.5 gene expression

Phenotypic expression

The physical traits that are expressed as a result of the interaction of gene pairs on homologous chromosomes.

Alleles

Alternative forms of the same gene found on corresponding pairs of homologous chromosomes.

Epigenetics

The study of how environmental factors influence gene expression and the role of the epigenome.

Epigenome

The collective chemical tags accumulated on DNA that influence gene expression without altering the DNA sequence.

Methylation of cytosine

The process of adding a methyl group to cytosine, influencing gene expression by inhibiting transcription.

Transcription factors

Molecules that bind to specific DNA sequences to regulate the transcription of genes.

Promoter sequence

A region on DNA where RNA polymerase binds to initiate transcription.

Activators

Proteins that bind to DNA and increase the rate of transcription.

Repressors

Proteins that bind to DNA and decrease the rate of transcription.

Acetylation of histone proteins

A modification that allows RNA polymerase to access genes by loosening the packing of histones.

Deacetylation

The process that condenses chromatin, limiting RNA polymerase access and inhibiting transcription.

Proto-onco genes

Genes that code for proteins involved in cell division and can be affected by epigenetic changes.

Tumor suppression genes

Genes that help prevent uncontrolled cell division and can be affected by epigenetic changes.

Cell differentiation

The process by which identical cells develop into specialized cells with distinct structures and functions.

Environmental factors and gene expression

Elements from the environment that can change patterns of DNA methylation and affect gene transcription.

Cancer

A condition caused by uncontrolled cell division, influenced by epigenetic factors affecting cell division genes.