Investigating CSI – Background material Table of Contents I ...

at this locus and a different sized band was produced. What could you do as an
investigator to be more certain that Jack was not the father of Payle?
Disease Status
In this example, we want to know if a person carries any cystic fibrosis (CF)
alleles and if so, how many. Because CF is a recessive disease, anyonne with
CF must be homozygous for disease alleles. From pedigree information, we can
often determine who in this family is a carrier. However, if a couple comes to a
genetic counselor, often an RFLP analysis is performed on the couple's DNA.
RFLPs are known for CF and so it would be easy to determine if a person were
homozygous wild-type (wt), heterozygous "carrier", or homozygous disease
alleles and thus have CF.
For couples expecting a child, it would be simple to test both parents and make a
prediction about the eventual disease status of their fetus. For example, if both
parents were homozygous wt, then all of their children would also be
homozygous wt:
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