You are part of a research team studying a recessive iron absorption disorder ca

Question

You are part of a research team studying a recessive iron absorption disorder called hemochromatosis. Your team has not yet mapped the gene that is causing the disease but you refer to it as the 'H' gene. You have a large table of marker genotypes and counts of 3000 affected and unaffected children from informative matings. As you scan through the table, you notice two markers that look like they might be associated with hemochromatosis. What is the order of the markers and the H gene on the chromosome? (Circle the best answer) G - B - H H - G - B B - H - G What is the genetic distance between Marker G and the H gene? There are 3000 total children. _ cM

Explanation / Answer

a)

Total number of individuals = affected + unaffected

                                             = 141 + 1281+ 6 + 69 + 69 + 9 + 1284 + 141 = 3000

Frequency of G2 marker = 141 + 69 + 1281 + 9 = 1500 / 3000 = 0.5

Frequency of G4 marker = 6 + 69 + 1284 + 141 = 1500 / 3000 = 0.5

Frequency of B1 marker = 6 + 69 + 1284 + 141 = 1500 / 3000 = 0.5

Frequency of B3 marker = 141 + 69 + 1281 + 9 = 1500 / 3000 = 0.5

The order of markers and H gene is G - B - H. Option i is correct.

b)

Distance between marker G and gene H is 1cM

Total number of children = 3000

Detection of marker G2 and G4 in unaffected = 141 + 69 + 1284 + 9 = 1503 / 3000 = 0.501

Detection of marker G2 and G4 in affected = 141 + 1281+ 6 + 69 = 1500 / 3000 = 0.5

Marker G = G2 + G4 in affected and unaffected = 0.5+0.5 = 1

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.