- The pedigree below is for an autosomal dominant disorder that has 100% penetrance.
- Determine the genotype for each individual and write in the box below their symbol. (3pts)
- Which allele for the STRP is most likely in coupling with the disease allele?______ (1pt) NOTE: We also say this allele is in phase with the disease allele
- In the same box, indicate whether each of the seven grandkids is a recombinant (R) or non-recombinant (NR) between the STRP and the disease allele.
How many recombinant individuals?_________(1pt)
How many non-recombinant individuals?_________(1pt)
- Estimate the value of Èmax for this pedigree? _________ (1pt) (HINT: It is equal to the fraction of recombinants over total.)
- Based on data from #4, write the equation relating Z to È for this pedigree. (2pt)
- Calculate Zfor È = 0. __________(2ðô)
- Calculate Zmax (i.e., Z value at Èmax).__________(2pt)
- Circle your interpretation for the value of Zmax for this pedigree? (1pt)
- linked ii) suggestive linkage iii) not linked
- What is your rationale? (1pt)
11. The table above gives the Z scores for four different marker loci (A, B, C and D) with respect to possible linkage to a monogenic, fully penetrant trait.
a. Which markers is/are significantly linked to the trait allele anywhere within 0≤È≤0.2? ________(1pt)
b. Which marker appears to be closest (fewest cM away) to the trait allele? _________(1pt)
c. Which markers, if any, definitely is/are NOT linked to the trait allele specifically at È=0? ________(1pt)
(they may be linked at other values of È)
d. For which markers, if any, can we make no definite conclusion about linkage? ________(1pt)
3. The table above shows the Z vs. È curves for a single marker but for five different family pedigrees.
a. Is this marker likely to be linked to the causal trait allele (within È≤0.2)? Yes No (1pt)
b. If so, about how far (in cM) from the marker do you think the trait allele is?_________cM (1pt)
c. The Z value in family 4 is negative at all È? Suggest an explanation. (1pt)