10 Ch12 Chromosomal basis for inheritance (Linked genes) AP Bio

If results of a genetic cross do NOT follow Mendel's Law of Independent Assortment, genes are likely to be - - - 

• shuffled during meiosis

• linked

• inherited

• on separate chromosomes

Which genes are most likely linked (likely to be inherited together)?

• genes 1 & 2

• genes 2 & 3

• genes 3 & 4

• genes 1 & 4

The reason some linked genes may get separated during gamete formation is - - - 

• genes aren't on the same chromosome
• genes don't compliment each other well
• a crossing over event shuffles the genes
• an environmental impact forces the genes to shuffle

Given the crossover frequency of each of the following genes, which pair genes are farthest apart on the chromosome

Gene Crossover Freq.

A-C            30%

B-C            45%

B-D            40%

A-D            25%

• B and C

• B and D

• A and C

• A and D

 CROSS I. Purebred lines of wild-type fruit flies (gray body and normal wings) are mated to flies with black bodies and vestigial wings.    F1 offspring all have a normal phenotype.   CROSS II. F1 flies are crossed with flies recessive for both traits (a testcross).  Result. Offspring          Normal   Percent  Gray body; normal wings  585     26.1 Black body; vestigial wings 581   25.9 Black body; normal wings  567    24.2 Gray body; vestigial wings  558   25.8 Based on the above information, choose the best answer for the following statement: Vestigial wings are a recessive trait

• None of the F1 flies had vestigial wings

• The parent generation had vestigial wings

• Most of the flies in the F2 generation had vestigial wings

• None of the flies in the F2 generation had vestigial wings

 CROSS I. Purebred lines of wild-type fruit flies (gray body and normal wings) are mated to flies with black bodies and vestigial wings.    F1 offspring all have a normal phenotype. 
 CROSS II. F1 flies are crossed with flies recessive for both traits (a testcross).
 Result. Offspring          Normal   Percent
 Gray body; normal wings  575     25.1
Black body; vestigial wings 571   24.9
Black body; normal wings  577    25.2
Gray body; vestigial wings  568   24.8
Based on the above information, choose the best answer for the following statement:
The genes for body color and wing shape are linked. 

• CROSS I results give evidence supporting the statement.
• CROSS I results give evidence against the statement.
• CROSS II results give evidence supporting the statement.
• CROSS II results give evidence against the statement.  

Hemophilia is a recessive x-linked disorder.
Which genotype represents a female who is a carrier for hemophilia?

• X^HX^h
• X^hX^h
• X^HX^H
• X^hY

Hemophilia is a recessive x-linked disorder.
Which genotype represents a male with hemophilia?

• X^HX^h
• X^hX^h
• X^HY
• X^hY

Colorblindness is a recessive x-linked disorder.
Which genotype represents a male with normal vision?

• X^NX^N
• XⁿXⁿ
• X^NY
• XⁿY

Colorblindness is a recessive x-linked disorder.
Which genotype represents a female who is colorblind?

• X^NXⁿ
• XⁿXⁿ
• X^NX^N
• XⁿY