dihybrid inheritance Flashcards
1
Q
what is a dihybrid cross
A
genetic cross where the inheritance of two genes is considered at the same time
2
Q
how many alleles are shown at each stage of a dihybrid cross
A
4 alleles (two for each characteristic)
3
Q
what is a common example of dihybrid inheritance?
A
use of peas - yellow round and green wrinkly
4
Q
what 6 things must be shown in a genetic cross?
A
- parental phenotype
- parental genotype
- possible gametes
- offspring genotype
- offspring phenotype
- proportion of each phenotype
5
Q
what will happen if a homozygous dominant allele is crossed with a homozygous recessive allele?
A
all offspring will be heterozygous
6
Q
what is the phenotypic ratio given when two heterozygous parents are crossed?
A
9:3:3:1
7
Q
when would the 9:3:3:1 ratio not be seen in dihybrid inheritance?
A
- when there is autosomal linkage
- when there is crossing over in meiosis
8
Q
what does crossing over result in?
A
new combinations of alleles in gametes - so predicted gametes in punnet square may differ
