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
