Epigenetics Nature VS nurture

Polygenic control of traits

Most traits are controlled by multiple genes interacting, rather than a simple 1:1 ratio.

Environmental influence on phenotype

Factors like temperature, light, nutrition, or UV radiation that impact phenotype.

Proportionate heritability

The concept that an organism's phenotype is explained partly by genes and partly by environment.

Purely environmental phenotype

Phenotype determined entirely by environment, such as dyeing one's hair.

Purely genetic phenotype

Phenotype determined mainly by genes, such as blood type.

Mixed genetic and environmental phenotype

Phenotypes resulting from a mixture, such as genetic risk of obesity managed by diet.

Protein function modification

Environmental factors typically influence the performance of proteins rather than gene expression.

Epigenetics

Molecular interactions that modify gene expression by turning genes on or off without altering DNA sequence.

Transcription

Reading and copying out a gene sequence from DNA into mRNA.

Translation

Process where mRNA instructs ribosomes how to build a specific protein.

Epigenetic effect on transcription

Molecules increase or decrease transcription levels to alter protein amounts.

DNA methylation

Methyl groups attach to DNA nucleotides, typically silencing gene expression.

DNA demethylation

Removal of methyl groups from a DNA sequence, typically leading to gene expression.

Histone modification

Enzymes join methyl groups to histone tails to modify how tightly DNA is wrapped.

Tightly condensed DNA packaging

Makes genes more difficult to transcribe and less likely to be expressed.

Less tightly packed DNA packaging

Makes genes easier to transcribe and more likely to be expressed.

Epigenetics and cell differentiation

Regulates different cell types by turning off unneeded genes and promoting required ones.

Epigenetics and environmental response

Acts as a rapid feedback mechanism to help organisms respond to environmental changes.

Somatic heritability

Epigenetic changes passed onto daughter cells during mitosis throughout an organism's life.

Identical twins and epigenetics

Explains why identical twins become increasingly different as they age due to environmental exposures.

Gamete formation and epigenetics

Most epigenetic changes are erased during gamete formation, though a small proportion may persist.