Extensions of Mendelian inheritance 3 Flashcards
Mendelian Inheritance
Are inheritance patterns that obey the law of segregation & law of independent assortment
___________ alleles often cause a reduction in the amount or function of the encoded protein
Recessive allele
Wild allele
Alleles in a natural population
Mutant Alleles
Random mutations that alter preexisiting alleles
_______________ disrupt gene functions & don’t always express a functional gene & they are inherited by a recessive alleles
Random mutations
____________ alleles ususally contains a mutation that causes a defect in the synthesis of a protein
Recessive Alleles
What are the 3 ways that dominant mutant alleles usually exert their effects?
- Gain of function
- Dominant-negative mutations
- Haploinsufficiency
Gain of function mutation
Changes the gene (or protein encodedby a gene) so that it gains an abnormal (new) function (ex. Mutant gene may be overly expressed producing too much encoded proteins)
Dominant negative mutations
Changes a protein so that the mutant protein act against the normal protein (Ex. In heterozygote the mutant protein counteracts the effects of the normal protein which alters the phenotype)
Haploinsufficiency
Pattern of inheritance where a heterozygote (one which a functioning allele & one with a inactive allele) exhibits an abnormal or disease phenotype (Ex. Having extra fingerings)
Traits may skip a generation due to ________________
Incomplete penetrance
Incomplete pentrance
When an allele that is expected to cause a particular phenotype doesn’t
Expressively
Degree to which the trait is expressed
Norms of reaction
Refers to the effects of environmental varation on a phenotype
_____________ can affect the phenotype of an individual or species
Environment
Incomplete dominance
Occurs when two alleles produce a mixture of the two genotype as its phenotype (intermediate phenotype) (Ex. crossing red & white flowers & getting pink flowers)
Overdominance
Occurs when heterozygote have greater reproductive sucess (Ex. Sickle cell disease)
Multiple alleles
Genes that found in 3 or more alleles (Ex. The ABO blood groups which determines blood type)
Codominance
When two dominant alleless are both expressed
Sex - influeneced inhertiance
An allele is dominant in one sex but recessive in the oppsite sex (Ex. Girls have certain traits guys dont)
Sex-limited inheritance
Only one sex can inherit a certain trait (Ex. Guys have traits girls dont)
Lethal alleles
Alleles that could cause someone to die
Conditional lethal alleles
Lethal alleles that could kill someone under certain conditions
Semilethal alleles
Act only in certain groups of people
Pleiotropy
Occurs when a single gene has multiple effects on a phenotype
Gene interaction
When two different genes affect a single trait
Gene interaction can exhibit _____________ & _______________
Epistasis & complementation
Epistasis
When alleles of one gene masks the phenotype of alleles on another gene at a different location (locus)
Complementation
When an offspring is prodcued with a phenotype from parents that have the same or similar recessive phenotype
Due to ______________ loss of function alleles may have no effect on a phenotype
Gene Redundancy
Gene Redundancy
When one gene can compensate for the loss of function of another gene
