Genetics Biology test 2 Flashcards
Loss-of-function mutation
hypomorph (decrease)
null/amorph (absence)
Gain-of-function mutation
neomorph-mutation in the coding region leads to a new function
antimorph-altered molecular function that acts antagonistically
neutral mutation
a change in DNA sequence but no effect on protien function
co-dominance
if both alleles are present then both phenotypes are shown
Example: if a red and white flower crossed, then the offsrping will have red and white petals
epistasis
epistasis interactions occur when phenotypes are due to mutations in the same pathway, and thus can obscure each other
stands upon or hides another trait
complementation analysis
can determine if two mutations causing a similar phenotype are alleles of the same gene
good allele compensates for mutated allele
recessive epistasis
homozygous recessive hides other gene phenotype
dominant epistasis
dominant allele hides the other gene phenotype
complementary gene interaction
needed a dominant allele at two genes
novel phenotypes
heterozygous produced a new phenotype
example - squash
if A-B- disc
if A-bb or aaB- sphere
if aabb long
allelic series
can result in multiple dominant recessive relationships
incomplete dominance
can result in intermediate phenotypes
example: a cross between a red and white flower produce a pink flower
penetrance
how many affected individuals (have the genotype) express a phenotype
expressivity
the strenght of the phenotype
a major tool for analyzing inheritance patterns is
pedigree analysis
- detect (X-linked vs autosomal modes of inheritance)
- Major tool of genetic counselors to help advise
pedigree symbols
square - male
circle - female
line between male and female - mating
if there is a ^ then dizygotic twins
if there is a triangle then monozygotic twins
colored in shapes - affected individuals
half colored in shaped - heterozygous
colored circle within a normal circle - carrier of sex-linked recessive gene
x-linked inheritance
inheritance related to sex of parent carrying mutant allele
maternal effect
phenotypica traits are determined by the genotype of the mother rather than the zygotic genome
example - snails shell coiling
lethal mutations
can be recessive or dominant
if organism hase both affected genes then they die early in development
mitochondrial inheritance
shows strict maternal pattern of inheritance
autosomal chromosomes
22 pairs
contain autosomal traits
sex chromosomes
X and Y
last two pair of chromosomes
genoetypic sex determination
sex determination dependent on sex chromosomes
genic sex determination
organism doesnt have sex chromosomes, rather differnt alleles at one or a few loci in the genome define sex or “mating type”
