Non-mandelian Flashcards
Codominance
There are two or more alleles that are dominant in a phenotype.
Both alleles are expressed in heterozygous condition.
Ex: Red – RR, white – WW, red and white - RW
Incomplete dominance
Heterozygote shows an intermediate, blended phenotype
example:
RR = red flowers= RR
rr = white flowers=WW
Rr = pink flowers=RW
Multiple Alleles
2 or more alleles affect the phenotype equally & separately
multiple alleles are not
not blended phenotype
multiple alleles ex used is
human ABO blood groups
3 alleles
of ABO blood groups
IA, IB, i
IA & IB alleles are co-dominant
i allele recessive to both (type o)
Polygenic inheritance
where multiple independent genes have an similar effect on a single quantitative trait
phenotypes on a continuum
polygenic inheritance affect what human traits
skin color
height
weight
intelligence
behaviors
Sex linked traits
Genes are on sex chromosomes
autosomal chromosomes
chromosomes that don’t carry any genes that determine the sex of the individual.
in humans & other mammals, there are 2 sex chromosomes
x and y
xx female
redundant
xy male
not redundant
Y chromosome
gene name
SRY
what does the y chromosome do
sex-determining region
master regulator for maleness
turns on genes for production of male hormones
mutations: (all are recessive)
hemophilia
Duchenne muscular dystrophy
color-blindness
Environmental effects
Phenotype is controlled by both environment & genes
what is affected by the environment
Human skin color is influenced by both genetics & environmental conditions
Coat color in arctic fox influenced by heat sensitive alleles
Color of Hydrangea flowers is influenced by soil pH
A pedigree
is a family tree that describes the interrelationships of parents and children across generations
Inheritance patterns of particular traits can be traced and described using pedigrees
