Author Question: To express a polygenic trait: a. genes must interact with the environment. b. several genes must ... (Read 183 times)

cherise1989 · **on:** Jun 25, 2018

To express a polygenic trait:

a. genes must interact with the environment.
b. several genes must act together.
c. multiple mutations must occur in the same family.
d. penetrance must occur.

Question 2

The gradual increase in height among the human population over the past 100 years is an example of:

a. a polygenic trait.
b. a multifactorial trait.
c. crossing over.
d. recombination.

jordangronback · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

ANS: B
Polygenic traits are those that result from several genes acting together. When environmental factors influence the expression of the trait, the term multifactorial inheritance is used. When multiple mutations occur in the same family, the mechanism most likely responsible is termed germline mosaicism. Penetrance of a trait is the percentage of individuals with a specific geno-type who also exhibit the expected phenotype.

Answer to Question 2

ANS: B
The gradual increase in height is an example of multifactorial traits influenced by genes and also by environment. Polygenic traits result from several genes acting together. Crossing over is an abnormal chromosome structure. Recombination results from new arrangements of alleles.