Answer to Question #292446 in Genetics for Smilynne

Question

19. A child has type O blood, and her mother has type A blood. What is the mother's 

genotype? What are the possible genotypes for the father?

20. What is the difference between pleiotropy and polygenic inheritance? Give an 

example of a trait that exhibits each.

21. What makes a good study organism for genetic research? Give an example of a 

bad study organism and a good one.

22. Be able to interpret a pedigree chart and say what possible genotypes the children 

of two known parents can produce.

Answer 1

19. A child has type O blood, and her mother has type A blood. What is the mother's 

genotype? What are the possible genotypes for the father?

The mother’s genotype is AO

The possible genotypes of the father are BO, AO, OO

20. What is the difference between pleiotropy and polygenic inheritance? Give an 

example of a trait that exhibits each.

Pleiotropy inheritance is the ability of one gene to influence multiple characteristic’s while polygenic inheritance is when a particular trait is controlled by several genes.

An example of pleiotropy inheritance is autism

An example for polygenic inheritance is hair color

21. What makes a good study organism for genetic research? Give an example of a 

bad study organism and a good one.

A good study organism for genetic research is an organism that has a short generation time, has similarities to humans or other organisms being studied, easy to maintain, its development and growth is well understood and can be breed in a laboratory setting (restricted area).

An example for a good study organism is a mouse (Mus musculus)

An example for a bad study organism is a human being

22. Be able to interpret a pedigree chart and say what possible genotypes the children 

of two known parents can produce.

A pedigree chart is a chart that illustrates a family tree and displays the members of the family affected by a genetic trait. Considering the pedigree chart below:

·        Circles represent females

·        Squares represent males

·        Darkened circle or square illustrate the individual is affected by the genetic trait

In the first generation the parents produced two affected daughters. The genotype of the parents and daughter are:

·        The genotype for the mother is Aa

·        The genotype for the father is aa

·        The affected daughters have a genotype of aa and aa

In the second generation, the affected daughter married an unaffected male producing an unaffected girl and an affected boy. The genotypes are:

·        Affected daughter (aa)

·        Unaffected husband (Aa)

·        Unaffected girl (Aa)

·        Affected boy (aa)