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1. In progeny of the cross Aa Bb Cc x aa Bb Cc , what proportion will be A_ B_ C

ID: 51423 • Letter: 1

Question

1. In progeny of the cross Aa Bb Cc x aa Bb Cc, what proportion will be A_ B_ C_? How many different kinds of gametes can be produced by each parent?

2. In fruit flies (Drosophila melanogaster) the bn+ allele for wild type red dull eyes is dominant to the bn allele for brown eyes. Another gene affects wing shape; for this gene, the ct+ allele for wild type wingsis dominant to the ct allele, which gives "cut" wings, with jagged edges. A fly with dull red eyes and wild type wings was crossed with a fly that had dull red eyes and cut wings, and the following progeny were obtained:

16 dull red eyes, normal wings

14 dull red eyes, cut wings

5 brown eyes, normal wings

5 brown eyes, cut wings

What were the genotypes of the parents?

Explanation / Answer

Answer 1:This is the tri-hybrid cross AaBbCc x aaBbCc, we will draw Punnett Square.

The gametes of AaBbCc are ABC,Abc,ABc,AbC,abc,aBC,abC,aBc

The gametes of aaBbCc are aBC,aBc,abC,abc

ABC

(gamete)

abc

(gamete)

aBC

(gamete)

abC

(gamete)

Abc

(gamete)

aBc

(gamete)

ABc

(gamete)

AbC

(gamete)

aBC

(gamete)

AaBBCC

aaBbCc

aaBBCC

aaBbCC

AaBbCc

aaBBCc

AaBBCc

AaBbCC

abC

(gamete)

AaBbCC

aabbCc

aaBbCC

aabbCC

AabbCc

aaBbCc

AaBbCc

AabbCC

abc

(gamete)

AaBbCc

aabbcc

aaBbCc

aabbCc

Aabbcc

aaBbcc

AaBbcc

AabbCc

aBc

(gamete)

AaBBCc

aaBbcc

aaBBCc

aaBbCc

AaBbcc

aaBBcc

AaBBcc

AaBbCc

The proportion of A_B_C_ are

AaBBCC:AaBbCC:AaBbCc:AaBBCc

1:2:4:2

and the gamete produced by two parents are:

The gametes of AaBbCc are ABC,Abc,ABc,AbC,abc,aBC,abC,aBc

The gametes of aaBbCc are aBC,aBc,abC,abc

Answer 2: The genotypes of the parent will be bn+bnct+ct & bn+bnctct

ABC

(gamete)

abc

(gamete)

aBC

(gamete)

abC

(gamete)

Abc

(gamete)

aBc

(gamete)

ABc

(gamete)

AbC

(gamete)

aBC

(gamete)

AaBBCC

aaBbCc

aaBBCC

aaBbCC

AaBbCc

aaBBCc

AaBBCc

AaBbCC

abC

(gamete)

AaBbCC

aabbCc

aaBbCC

aabbCC

AabbCc

aaBbCc

AaBbCc

AabbCC

abc

(gamete)

AaBbCc

aabbcc

aaBbCc

aabbCc

Aabbcc

aaBbcc

AaBbcc

AabbCc

aBc

(gamete)

AaBBCc

aaBbcc

aaBBCc

aaBbCc

AaBbcc

aaBBcc

AaBBcc

AaBbCc