24) Lethality, lethal gene mutations in breeding Flashcards
1
Q
All individuals with lethal gene mutations will…
A
Die before sexual maturity
- Embryonic fatality
- Fetal fatality
- Prenatal fatality
- Postnatal fatality
2
Q
Most lethal genes are…
A
Recessive
- Lethal in homozygotes
- Heterozygotes are carriers
3
Q
Dominant mutation alleles…
A
- Rare
- Heterozygotes are carriers only
- Homozygotes will die
4
Q
Death in homozygotes leads to…
A
- Segregation ratio in F2 generation of 2:1
- Instead of 1:2:1
5
Q
Sublethal condition
A
More than 50% die
6
Q
Sub-vital condition
A
- More than 50% will live
- They will have defects
7
Q
Dominant lethal genes
A
- Yellow mutation in field mice
- Manx factor in cats
- Merle colour in dogs
- Silver fox platinum colour mutant
- Silver fox white face mutant
- Lethal white overo foals of paint horses
8
Q
Yellow mutation in field mice
A
- Embryonic lethality
- YY lethal
- Yy yellow coat
- 2:1 ratio
9
Q
Manx factor in cats
A
MXmx lethal (taillessness)
10
Q
Merle colour in dogs
A
- MM subvital
- Mm merle colour
11
Q
- Silver fox white face mutant
- Silver fox platinum colour mutant
A
Both embryonic lethality
