(non) Mendelian inheritance

autosomal recessive

two copies of an abnormal gene must be present in order for the disease or trait to develop

autosomal dominant

inheritance pattern of a dominant allele on an autosome

when drawing pedigree charts what is assumed

1/25 are carriers

autosomal dominant inheritance

each child has a 50% chance of inheriting mutation

sex-linked traits

Traits controlled by genes located on sex chromosomes.

incomplete penetrance

the genotype does not always produce the expected phenotype

genomic imprinting

variants from parents
genes that are imprinted (marked) are turned off

extranuclear inheritance

inheritance of traits determined by factors outside of nucleus (eg mitochondrial)

anticipation inheritance

triplet repeat expansion
becomes more prevelant

complex inheritance

multi gene risk

what is penetrance

The percentage of individuals with a specific genotype who also express the expected phenotype

what are the genetic mechanisms of imprinting disorders

deletions

point mutations

imprinting errors

uniparental disomy casing trisomy

mitochondrial inheritance

maternal

mutation hotspot

lack of DNA repair system

no protective proteins damaged by reactive oxygen species like free radicals

environmental factors in genetic disease

chemical

radiation

food

exposure to toxins etc