The pedigree below is for an autosomal dominant disorder that has 100% penetrance.

  1. 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)
  1.  linked      ii)  suggestive linkage             iii) not linked
  1. 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)