Lecture 14 - Human Molecular Genetics Flashcards
In what ways can monogenic defects cause disease?
- loss/gain of function in protein coding genes
- defective enzymes in metabolic pathways
What is dominant inheritance?
Vertical patterns of affected individuals
What is recessive inheritance?
Horizontal patterns of affected individuals (one generation)
What is autosomal recessive inheritance?
Consanguinity (incest) present between parents (seen by double line between parents on a pedigree)
What is autosomal (dominant) inheritance?
Males and females affected with equal probability (in each generation and both sexes on a pedigree but once a parent does not have it the child won’t either)
What is X linked recessive inheritance?
Males are effected, females are carriers (skips generation - not father to son but grandfather to carrier mother to son)
What is X linked dominant inheritance?
All daughters of males being effected
What is mitochondrial inheritance?
NOT Mendelian (everyone inherits condition from mother)
What 6 complications may affect the interpretation of pedigrees?
- New mutations that aren’t inherited
- Incomplete penetrance where not everybody has the gene
- Expressivity
- Delayed onset
- Anticipation where it’s gradually inherited earlier
- Imprinting (epigenetic changes)
What is cytogenetics?
Disease correlating with visible chromosome deletion or rearrangement
What 2 types of markers are used in genetic mapping?
Phenotypic: genetic disorders
Molecular: structural arrangement, SNPs, INDELs, STRs
How is a lod score calculated?
Log 10 x (odds loci are linked/ odds loci are unlinked)
What does a lod score or > 3.0 indicate?
Linkage
What is a GWAS?
Genome wide association study that uses a large population to determine association through lod score calculation
