Question

Chinese Shar Peis are dogs that are selectively bred by humans specifically for their wrinkly fur coat, small triangular ears, and broad muzzle. These traits are recessive and must be brought out by breeding similar dogs with the desired traits. Dominant Shar Peis are becoming less desirable, as the rare traits become more in demand.



Two-Part Question

Part A

Multiple Select Question

Which statement best describes how humans select for wrinkly skin in Chinese Shar Peis?

A. 

By mating a very wrinkly female and non-wrinkly male so they have the best chance of passing on the gene for wrinkly skin.

B. 

By mating a wrinkly female and wrinkly male so they have the best chance of passing on the gene for wrinkly skin.

C. 

By inserting a gene for wrinkly skin into every Shar Pei puppy.

D. 

By mutating the DNA of one Shar Pei, hoping they will pass on the mutated trait to their offspring.

Part B

Multiple Select Question

Chinese Shar Peis are selectively bred for their recessive trait, the wrinkly coat. The genotypic relationship of (rr) represents pure recessive genes. What would the alleles of the parents need to be in order to pass those traits to at least 25% of the offspring? Select three that apply:

A. 

RR, RR

B. 

Rr, Rr

C. 

RR, rr

D. 

Rr, rr

E. 

rr, rr

Answer 1

### Part A

The statements that best describe how humans select for wrinkly skin in Chinese Shar Peis are:

**B. By mating a wrinkly female and wrinkly male so they have the best chance of passing on the gene for wrinkly skin.**

### Part B

To pass the recessive trait (rr) to at least 25% of the offspring, the following parental allele combinations would work:

**B. Rr, Rr**
**D. Rr, rr**
**E. rr, rr**

These combinations would allow for at least 25% of the offspring to exhibit the desired recessive trait of wrinkly skin (rr).