Chapter 16 Parents to offsspring 2

Epigenetics

The study of mechanisms that lead to changes in gene expression without altering the DNA sequence.

Epigenetic inheritance

The passage of an epigenetic change from parent to offspring via sperm or egg cells.

Genomic imprinting

A process by which genes are marked so that only the maternal or paternal allele is expressed.

DNA methylation

An epigenetic marking process where methyl groups are added to DNA, usually silencing gene expression.

X-chromosome inactivation (XCI)

An epigenetic change in female mammals where one of the two X chromosomes is inactivated.

Barr body

The highly compacted and inactivated X chromosome in female mammals.

Maternal inheritance

The pattern of inheritance where genes located in organelles such as chloroplasts are passed only from the mother.

Agouti gene

A gene that influences coat color in mice and is affected by diet-related epigenetic changes.

Phenotype

The observable physical and physiological traits of an organism, determined by genetic and environmental factors.

Linkage

The tendency of genes located closely on the same chromosome to be inherited together.

Crossing over

The process during meiosis where homologous chromosomes exchange genetic material, creating new combinations of alleles.

Extranuclear inheritance

The transmission of genetic information located outside the nucleus, primarily in mitochondria and chloroplasts.

Linkage group

A group of genes that are linked together on the same chromosome and are usually inherited together.

Calico cat

A female cat with a coat color pattern caused by X-chromosome inactivation.

Covalent histone modification

An epigenetic change involving the addition of chemical groups to histone proteins, affecting gene expression.

Chromatin remodeling

The structural alteration of chromatin that can affect gene accessibility and expression.

X inactivation center (Xic)

A region on the X chromosome crucial for the process of X-chromosome inactivation.

Mitochondrial genome

The DNA contained within mitochondria, typically inherited maternally.

Chloroplast genome

The DNA contained within chloroplasts, responsible for encoding proteins vital to photosynthesis.

Epigenetic modification

A change in gene expression that does not involve a change in the DNA sequence, often influenced by environmental factors.

Transcription repression

The process by which gene expression is inhibited, often through epigenetic changes.

Somatic cell

Any cell of a living organism other than the reproductive cells.

Heterozygous

Having two different alleles for a specific gene.

Dependency between genes

The concept that the inheritance pattern of one gene may depend on the inheritance pattern of another gene when they are linked.

Environmental agent

Any external factor, such as chemicals or nutrients, that can induce epigenetic changes.

Imprinted gene

A gene whose expression is determined by the parent from which it is inherited, with only one parent's allele being expressed.

Phenotypic variation

Differences in appearance or function among individuals due to genetic or environmental influences.