Chapter 4 book Flashcards
what does wild type allele produce
produce enzyme with full activity
what does mutant allele produce
little enzyme activity
If WT is dominant and mutant is recessive R+ produces 50 units of enzyme activity and r produces no functional enzyme list the genotypes and amount of enzyme activity. Also, 40 units of of enzyme activity is needed to produce genotype
Homozygous Dominant R+R+ is 100 units
Heterozygous R+r is 50 units
Homozygous Recessive rr is 0 units
Haplosuffcient
Dominant WT alleles due to 1 copy sufficient to produce WT phenotype
If WT is recessive and mutant is dominant T1 produces 10 units of enzyme activity and T2 produces 5 units of enzyme activity list the genotypes and amount of enzyme activity. Also, 18 units of enzyme activity is needed to produce genotype
Homozygous recessive T1T1 20 units
Heterozygous T1T2 15 unit
Homozygous Dominant T2T2
Haploinsufficient
1 copy not enough to make wild type
loss of function mutation
Significant decrease or complete loss of functional activity of gene product
gain of function mutation
identify alleles with new functions or expression altered for more activity than WT
null mutation
complete loss of gene function in comparison with wild type genes
What type of mutation is a lethal homozygous genotype and why
Null mutation because it blocks transcription of gene product that lacks activity or deletion of gene
leaky mutation
partial loss of gene
dominant negative mutations
change polypeptides from interacting normally to produce functional proteins which prevents polypeptide interactions normally produced
hypermorphic mutation
produce more gene activity per allele than wild type and is dominant and result from regulatory mutations
neomorphic mutations
acquire new activities not found in wild-type dominant
Describe the notation system for genes
uppercase is dominant and lowercase is recessive
If not complete dominance different notation used
+ for WT and - for mutant
incomplete dominance
phenotype of heterozygous distincitive
codominance
heterozygous phenotype different form phenotype of homozygous parents and both alleles are expressed in heterozygotes
List genotypes for the phenotypes of blood types
Type A: IAIA, IAi
Type B: IBIB, IBi
Type AB: IAIB
Type O:ii
Allelic Series
Group of alleles that display hierarchy of dominance relationship among them
Discuss C gene system of mammalian coat color
Allele C dominant to all and is wild type
Cch= diluted coat color is hypomorphic
Ch= fully pigment extremities but rest of body no pigmentation and is temperature sensitive
c= no enzymatic activity
C>Cch>Ch>c
lethal alleles
certain mutations cause early death or termination usually in homozygous
Detection of lethal alleles in plants
embryonic lethals that fail to produce homozygous lethal or gametophyic lethals that fail to generate lethal allele carrying gametes
Detection of lethal alleles in animals
detected when segration ratios distorted due to failure to produce affected catagroy
delayed age of onset
abnormalities do not appear until organisms reproduce
Complete pentrance
phenotype always produced with genotype
Sex limited traits
both sexes carry genes but 1 sex shows it
Example of sex limited traits
development of breast
Sex influenced traits
inheritance pattern for 1 sex differs from inheritance pattern for the other sex even when genotype is the same
pentrance
organism phenotype consistance with genotype
nonpentrance
organism with particular genotype fails to produce phenotype
fully penetrant
genotype always expressed
Incomplete prentrant
nonpentrant
variable expressivity
Same genotype produces phenotype in varying degree
Why is it hard to pinpoint incomplete and variable
both modify the expression, environmental or developmental
Gene-environment interaction
Influence of environment factors on expression
What can PKU be treated if it is known about
dietary management since it cant break down protein
pleiotropic
alteration of multiple features of phenotype by 1 mutation
Gene interaction
collaboration of multiple genes to make one phenotype character
Who made the 1 gene 1 enzyme hypothesis
beadle and tatum
1 gene 1 enzyme hypothesis
each gene produces enzyme and each enzyme has specific role in pathway
what happens if there is a mutant phenotype according to 1 gene 1 enzyme hypothesis
loss or defective fuction of emzyme
prototroph
wild type
auxotroph
mutant
changes of 1 gene 1 enzyme hypothesis
many genes make transport proteins, structural proteins, RNA and some proteins join together to make function
explain biosynthetic pathways
sequential step to be completed where 1 step creates substrate for next step and completion of every step needed for production
genetic dissection
test ability of mutant to execute each step of pathways and assemble steps of pathway
epistatic interactions
result from gene products interacting in pathways
No interation phenotype
9:3:3:1
completmentaty gene interaction
9:7 where 9= C_P_ and 7= ccP_,C_pp, and ccpp
Gene works in tandem to make 1 product
recessive epistatsis
9:3:4 where 9=B_E_, 3= bbE_, and 4=B_ee or bbee
Genetic heterogeneity
mutations of different genes produce same or similar phenotypes
Genetic complementation analysis
experimental analysis of crosses to test alternative genetic explantations
complementaiton group
fail to complement each other - sign on chart and are on same gene
