Two autosomal genes controlhorn color in dragons. Pure-breeding gold-horned drag
ID: 312678 • Letter: T
Question
Two autosomal genes controlhorn color in dragons. Pure-breeding gold-horned dragons were mated to pure-breeding silver-horned dragons. All of the F1 were gold. The F1 were intermated and he F2 generation consisted of 139 gold, 16 silver and 93 bronze.
Choose the genetically based phenotypic ratio that should be hypothesized to explain the F2 data.
Select one:
9:3:3:1
9:3:4
12:3:1
9:7
15:1
9:6:1
13:3
Conduct a chi square test to test the appropriate type of epistasis. In the chi-square test, what is the expected number of gold-horned dragons? Round to two decimal places.
_______
What is the expected number of silver-horned dragons? Round to two decimal places.
_______
What is the expected number of bronzehorned dragons? Round to two deicmal places.
_______
What is the chi-square value? Round to three decimal places.
______
What is the number fr the degrees of freedom?
______
What is the critical value? Round to two decimal places.
______
What is your conclusion fromthe chi-square test?
Select one:
Fail to reject H0
Reject H0
Explanation / Answer
The ration of the F2 generation obtained from the cross between the F1 gold phenotyped dragons is 9:6:1 ( 9 gold: 6 bronze: 1 silver ).
It is due to duplicate genes due to cumilative effect.
Let 'A' be the allele for Gold horn color and 'a' be the allele for silver
AABB (gold horn) X aabb ( silver horn)
F1 - AaBb( Gold horn)
0.56 is expected number of gold-horned dragons
0.062 is the expected number of silver-horned dragons
0.375 is the number of bronzehorned dragons
AB Ab aB ab AB AABB AABb AaBB AaBb Gold horned Gold horned Gold horned Gold horned Ab AABb Aabb AaBb Aabb Gold horned bronze horned Gold horned bronze horned aB AaBB AaBb aaBB aaBb Gold horned Gold horned bronze horned bronze horned ab AaBb Aabb aaBb aabb Gold horned bronze horned bronze horned silver