Heritability and non-Mendelian inheritance

How can heritability be estimated?

Comparing parents and offspring

Twin studies

Pedigrees

Monozygotic twins

Genetically identical twins who share a similar environment

Dizygotic twins

genetically non identical and share a similar environment

Genetic concordance

the proportion of cases in which both members of a pair of twins show a trait

GWAS

genome wide association studies

Epigenetics

the inheritance of variation beyond differences in DNA base sequence. Changes are inherited by descendent cells and (maybe) descendent individuals.

Thrifty phenotype hypothesis

inherited genetics that prepare the individual for poor life conditions

What molecular processes lead to epigenetic changes in chromatin structure?

Changes in patterns of DNA methylation - inhibits transcription factors from binding so RNA polymerase can't be recruited

Histone modifications - addition of phosphates, methyl groups, acetyl groups and ubiquitin

RNA molecules - e.g. X-chromosome inactivation

How do rats experience less fear and reduced stress in adulthood when groomed more by parents as pups?

DNA methylation (impacts histone acetylation) causes the difference

PRC

polycomb repressive complex (proteins that produce epigenetic marks)

Paramutation

an interaction between two alleles that leads to a heritable change in expression of one of the alleles (The DNA base sequence remains the same)

Genomic imprinting

some genes are expressed more if they are inherited from the father and others if they are inherited from the mother