Genetics-Inheritance Flashcards
Autosomal Dominant Inheritance
onle needs 1 allele of a gene to be expressed
affected child only needs one affected parent
unaffected person will not transmit
no sex link
trait expected every generation
50% recurrence risk
Autosomal Recessive Inheritance
2 copies needed of the allele to be expressed
one copy will make person carrier (50%)
two copies will make the person affected (25%)
no copies will make the person unaffected (25%)
X-linked Recessive
males with this are called hemizygous
female rarely affected due to lyonization, can be heterozygous or homozygous.
always expressed in male carried
unaffected males will not transmit
female carries transmit allele to 50% of sons and 50% daughters
all daughters of afffected males are heterozygous carriers
never father to son transmission (x linked)
Mitochondrial DNA is important because
it encodes rRNA, tRNA, 13 polypeptides needed for OxPhos
MUTATION IS 10X HIGHER THAN nDNA
due to no DNA repair mechanisms, damage from free oxygen radicals from ox phos
Mitochondrial disorders include
LHON
MERF
MELAS
see disorders set for details
X-linked dominant
very rare, no carriers
males with dz allele transmit the traits only to daughters 100% of the time
females with the dz allele transmit the trait to males and females, 50% of the time
polyploidy
cells contain a complete set of chromosomes in the cells (plants)
aneuploidy
cells contain an individual extra or a missing chromosome (monosomy, trisomy)
Nondisjunction causes
aneuploidy
Genomic Imprinting
certain genes are only expressed from one parent, and other parent is silenced
imprinted allelse are silenced such that the gene expressed only from the NON imprinted allele of the mother or father
involves methylation/histone modifcation of eggs/sperm and is duplicated in allt he somatic cells
uniparental disomy
someone receives two copies of a chromosome or part of a chromsome from one parent and none from the other parent
usually no sx because the child has another copy of each gene
if this occurs on imprinted genes, can be developmental delays, MR, other issues
Prader Wili occurs from UPD on an imprinted gene on the long arm of chromsome 15
causes parent specigic imprinting
in genomic imprinting, the allele transmitted from teh motehr would be
inactive and the same allele transmitted by the father would be active
phenotypically normal person would only have one transcriptionally active copy of that gene
imprinting is gene silencing via
methylation of the 5/ region of gene, chromatin condenses
epigenetics imprints remain throughout lifespan in
somatic cells
reset at each generation in meiosis
