chapter 5 Flashcards
SNPs (single nucleotide polymorphism)
single base change anywhere in genome
mapping with molecular markers
- mapping by DNA sequencing
- SNPs (single base change) and RFLP (SNP that alters enzyme recognized sequence)
RFLPs (restriction fragment length polymorphism)
SNP that alters sequence recognized by enzyme
Snip SNPs
restriction site polymorphism
microsatilite markers
repeats of sequences
FISH (floresenct insitu hybridization)
reveals sites and position of single genes on condensed chromosome
genetic maps show us
- determines if trait/disease is caused by varience of single gene
- liklihood of trait inheritence
- recombo
does dominance alter how genes are inheritted
No
dominance is interaction of…
products of genes
phenotype depends on
allele combination
amorph/null allele
complete loss of gene function
hypomorph
partial loss of gene function (reduction in expression or activitiy)
haplosuffient vs haploinsufficient
haplo - recessive
haploin - dominant
loss of function mutations are usually…
recessive
gain of function mutations are usually…
dominant
hypermorph
increase in normal gene function, dominant
antimorph/dominant negative
dominant and oppose normal gene function
neomorph
dominant gain of gene function
dominant negative
interferes with function of wild type gene function
phenocopy
loss of gene function
complete dominance
phenotype of homo and hetero are the same
incomplete dominace
heterozygous is it’s own phenotype (1:2:1 ratio)
codominance
each allele has distinct gene product, both alleles detected in heterozygote
codominance example
blood type
lethal alleles
cause premature death
recessive lethel
if both parents are carriers, 1/4 chance of death and 2:1 ratio
conditional mutants
lethals isolated and can be manipulation
permissable
viable
restrictive
dead
sublethal
incompletely expressed
reasons for an unclear genotype…
-varying degrees of dominance
- multiple alleles at each locus
- lethal allele
penetrance
all individuals have same mutant genotype but not all are phenotypically mutant
expressivity
degree that genotype is expressed
complimentation test
mate 2 mutants, if the progeny are homo recessive they are on the same gene
double mutants
combine mutants in pairs and see if genes interact
infer gene interaction based on…
mendalian ratios (2 indepenent is 9:3:3:1)
epistasis
effect one gene pair (masks or modifies) on another gene pair
linear pathway
genes are linearly converted to product
parallel pathway
genes are converted to other genes that combine to end product
prototroph
can grow on minimal mediaa
auxotroph
needs nutritional substance and minimal media for growth
recessive mutations in same path have a … ratio
9:7 ratio
Recessive epistasis ratio
9:3:4
epistasis in biosynthetic path
mutation in upstream gene is epistatic to downstream gene
epistasis in regulatory development path
mutation in downstream is epistatic to upstream gene
dominant episasis ratio
12:3:1
modifiers
mutations that supress or enhance phenotype of other mutants
supressor mutant
second site mutation that reverses affect of another mutant
enhancer mutant
second side mutant that increases affect of another mutation
recessive supressors segregate in a __ ratio
13:3
