Looking for classes? Ksquare Career Institute, Bengaluru →
Principles of Inheritance and Variation
Linkage Maps
2 questions from 2 papers, each with its answer.
- questions
- 2
- papers
- 2
- of Principles of Inheritance and Variation
- 1.01%
Appears in
Concepts tested
- Gene order from recombination frequencies
- Genetic map from recombination frequencies
All Questions
2003 AIPMT 1 question
-
Genetic Map is one that : -A genetic (linkage) map shows the relative positions (sites) of genes on a chromosome and the distances between them.
It is prepared from the recombination frequencies between linked genes: 1 percent recombination = 1 map unit (centimorgan). Alfred Sturtevant made the first genetic map in Drosophila.
So a genetic map is one that establishes the sites of the genes on a chromosome.
2002 AIPMT 1 question
-
There are three genes a, b and c. The percentage of crossing over between a and b is 20%, b and c is 28% and a and c is 8%. What is the sequence of genes on chromosomeMap distance is proportional to the frequency of crossing over: a–b = 20 units, b–c = 28 units, a–c = 8 units.
The largest distance (b–c = 28) is between the two genes at the ends.
The third gene, a, lies between them: b–a + a–c = 20 + 8 = 28 = b–c.
[add image: linkage map b ---20--- a --8-- c]
So the sequence of genes on the chromosome is b, a, c.