The Rh blood group in humans is determined by a gene on ...

Question

The Rh blood group in humans is determined by a gene on chromosome 1. A dominant allele produces Rh+ blood type, and a recessive allele generates Rh-. Elliptocytosis is an autosomal dominant disorder that produces abnormally shaped red blood cells that have a short life span resulting in hereditary anemia. A large family with elliptocytosis is tested for genetic linkage of Rh blood group and the disease. The lod score data below are obtained for the family.

What is Zₘₐₓ for this family?

Graph showing lod score data for genetic linkage of Rh blood group and elliptocytosis in a family.

Accepted Answer

Hello, everyone. Let's look at our next question. It says in a three point mapping experiment. Gene A is 15 map units away from gene B And 25 map units away from gene C. How far apart are genes B and C on the map? And our answer choices are choice A 10 Centam Morgans B 15 Centam Morgans, C 25 Centam Morgans and D 40 Cent Notes. Well, the first thing to recall as we look at our answers and our question, our question is given the distance in map units and our answers are in centam organs. So we just have to remember the simple fact that one map unit equals one centam organ. So that takes care of that. So now let's sort of diagram the information we already have. We have genes A and B which have a distance of 15 map units apart. So I've drawn a little line between A&B labeled 15 map units. And then we've got a, it's 25 map units away from G and C. So I'll extend that line and put C at the end and I'm going to label the distance from A to C as 25 map units. And then my question is, how far apart are Genes, B and C? Well, I know from A to B is 15, from a to C is 25. So the distance between B and C must equal 25 map units minus 15 map units. And therefore that will equal 10 map units, which will be the same thing as 10 Centam Morgans. So when we look at our answer choices, choice A is 10 Centam Morgans. So that is our distance that B and C are apart. Nice easy one for us. Hope to see you in the next video.

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