Lecture 4: Analysis of Single Loci and Chromosomal Haplotypes - Using Complementation Tests and Family Data

t/f: our genetic and genealogic ancestors are the same

false: the vast majority of genealogical ancestor are not your genetic ancestors

t/f: The further back in time you, your genetic ancestors are a smaller and smaller a subset of your genealogical ancestors

true: because the further back you go the more and more people we are related too

genetic ancestors

an individual from whom you have directly inherited a specific segment of DNA

genetic model organism

yeast, fruit fly, mouse, E.coli

why are genetic model organism so good?

• can be crossed and experimentally manipulated in labe

• short generation time

• large numbers of progeny

why are pedigree useful?

• allow for the investigation of genetic diseases in closely related individuals

• is a way of deducing inheritance when information is limited

ex: used for rare gentic diseses

t/f: in a disease pedigree we can assume that unrelated indiviuals marrying into a family are homozygous wild-type

true: unless otherwise mentioned shown

t/f: recessive disease traits show a pattern of unaffected parents having an affected child

true: both parents must be heterozygous if child is affected

x-linked recessive trait

are most common in males bc they only get one x chromosome from mom while females can get it from either mom or dad

t/f: If an X-linked disease is associated with a dominant allele, affected males produce all affected daughters and no affected sons.

true

t/f: autosomal dominant traits appear in each generation.

true

what is the forward genetic approach

Start with a weird trait, then find the gene that caused it.

1. make or find mutants with traits of interest

2. find mutant gene in the genome (via genetic mapping)

3. Study the gene to learn how it normally functions

auxotrophs

organisms that cannot survive in minimal media

complementation test

crossing two auxotrophic mutations to see if the mutations are in different genes

if they are then the diploid would be able to synthesize arginine

With respect to a trait, if two mutant strains fused result

in a mutant diploid, this indicates that the strains had

mutations in the same gene relevant to the trait

prototroph

organisms that can survive in minimal media

supplementation test

supplementing auxotrophic mutants with different substrates in the Arginine Biosynthesis Pathway to see which genes are relevant to which steps/enzymes in the in the Arginine Biosynthesis Pathway

genealogical ancestor

any biological individual who occupies a specific spot on your family tree, regardless of whether you inherited their DNA