Breaking the laws of inheritance Flashcards
1
Q
What are the placental mammals - female chromosomes?
A
- the female has two X chromosomes
- homogametic
2
Q
What type of chromosomes does a male placental mammal have?
A
- Male has one X and one Y
- heterogametic
3
Q
In birds/snakes what chromosomes will the male have?
A
- make had two Z chromosomes
- homogametic
4
Q
In birds and snakes what chromosomes do the females have?
A
- female has one W and one Z
- heterogametic
5
Q
What are sex linked genes like in the homogametic sex?
A
- sex-linked genes can be homozygous or heterozygous
6
Q
What are sex linked genes like in the heterogametic sex?
A
- sex linked genes are usually hemizygous (1 copy)
- for mammals
7
Q
What is epistasis?
A
- genes interact to affect a single trait
8
Q
What is recessive epistasis?
A
- homozygous recessive allele at one locus
- masks expression of alleles at another locus
9
Q
What is dominant epistasis?
A
- dominant allele at one locus
- masks expression of dominant and recessive alleles at another locus
10
Q
What is dominant inhibitory epistasis?
A
- dominant allele at one locus
- masks expression of dominant allele at another locus
11
Q
What is duplicate recessive epistasis?
A
- homozygous recessive allele at first locus
- masks expression of dominant allele as second locus
12
Q
What is duplicate dominant epistasis?
A
- dominant allele at first locus
- masks expression of recessive allele at second locus
Or
- dominant allele at second locus
- masks expression of recessive allele at first locus
13
Q
What is a mendelian trait?
A
- very obvious traits like colour
14
Q
What are quantitative traits?
A
- a gradual change such as height
15
Q
What happens as the number of genes contributing to a trait increases?
A
- number of genotypes increases
- distribution of trait values approaches normal distribution
