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In Drosophila black body (B) is dominant to gray (b) and long wings (L) is dominant...

In Drosophila black body (B) is dominant to gray (b) and long wings (L) is dominant to short wings (l). The F1 flies were produced by crossing a homozygous black, homozygous long winged fly with a gray short winged fly. (4)

a) Give the genotypes of the Parents and the F1.

b) If an F1 is testcrossed, what is the expected phenotypic ratio?

c) If the F1 are allowed to interbreed what are the expected phenotypes and probably proportions in the F2 generation?

d) If the F1 is mated with a true breeding black and long winged fly, what would be the expected phenotype(s) and the probably proportions of the F2 generation

Solutions

Expert Solution

a) Give the genotypes of the Parents and the F1.

Parents genotype:

homozygous black, homozygous long winged fly =BBLL

gray short winged fly=bbll

All the F1 flies will be BbLl

Phenotype=heterozygous with black body and long wing

b) If an F1 is testcrossed, what is the expected phenotypic ratio?

BbLl x bbll

	BL	Bl	bL	bl
bl	BbLl	Bbll	bbLl	bbll

1:1:1:1

1 black body and long wing

1 black body and short wing

1 Grey body and long wing

1 Grey body and short wing

c) If the F1 are allowed to interbreed what are the expected phenotypes and probably proportions in the F2 generation?

BbLl x BbLl

9 black body and long wing

3 black body and short wing

3 Grey body and long wing

1 Grey body and short wing

d) If the F1 is mated with a true breeding black and long winged fly, what would be the expected phenotype(s) and the probably proportions of the F2 generation

BbLl x BBLL

	BL	Bl	bL	bl
BL	BBLL	BBLl	BbLL	BbLl

All the F2 flies will be of black body and long wings

gladiator answered 1 year ago

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