In sickness and in health-Greg and Olga

http://www.sciencecases.org/sickness_and_health/sickness_and_health.asp

Pedigree of Greg and his family.

Pedigree of Olga and her family.

Myotonic Dystrophy, autosomal dominant:

Do autosomal dominant disorders skip generations?

no, they can't. if it isn't passed on then it won't be able to continue on down the line

Could Greg or his mother be carriers of the gene that causes myotonic dystrophy?

Greg and his mother do not have the disease and will not be affected by it, thus they cannot be a carrier of the gene because MD is automal dominant which means there is a 50-50 chance of getting the disorder. There are only people that are affected by autosomal dominant genes, not carriers.

Is there a possibility that Greg’s aunt or uncle is homozygous for the myotonic dystrophy (MD) gene?
In order to be homozygous for a gene, one must have either two dominant or two recessive genes (ex: AA,aa). the only way for this to happen with the MD gene is to have the dominant trait passed on from both the mother and the father. Now, seeing how only Gregs grandma was affected by MD and his grandpa wasn't, it is not possible for his afflicted aunt or uncle to be homozygous for the myotonic dystrophy gene.

What is the possibility that Greg and Olga’s children could inherit the MD gene?
It is not possible that their children could inherit the MD gene. This is because Greg is not a carrier of the gene and Olga has no history of MD in her family.

Factor VIII, autosomal recessive:
What are the hallmarks of an autosomal recessive trait?
An autosomal recessive trait skips generation and can be carried while not affecting the carrier.This is because it is a recessive trait and can only afflict a person when they inherit two recessive traits.


What does consanguineous mean? Why is this concept especially important when discussing recessive genetic disorders?

consanguineous means that the pair in the relationship shares a common bloodline, they are from the same ancestor. (someone found that long lost relative that was twice removed after being accepted again after being removed six other times(i think anyway) http://www.biology-online.org/dictionary/Consanguineous) This concept is important because of how recessive genetic disorders require two recessive traits. If the pair mating are from the same blood line then the chances of having the autosomal recessive trait is much more likely, thus ending up with a child with the recessive disease.

What is it about the inheritance pattern of factor VIII deficiency seen in Greg and Olga’s pedigree that point toward it not being an autosomal recessive trait?

The factor VIII deficiency in Greg and Olga's pedigree point towards it being sex linked because it has only affected a few males in the family. To point towards it being autosomal recessive, it will need to have affected both males and females.