Book : Molecular Biology
posted by
Posted by: CHELSEA
posted by
Writer CHELSEA

Double Crossovers

image about


Overview

If all three markers are in the same linkage group, that is, on the same chromosome, then we can observe an ABC/abc undergoing two recombination events, one between A and B, and another between B and C, to give AbC/aBc. This is what is going on in cells 7 and 8 of the earlier example. If we had been looking only at dihybrid test cross data, then we would not be able to detect these double recombinants. One notices that double recombinants are not very common, so the effect on the estimates of the percent recombination is not large. The corollary of this is that most chromosomes will experience only zero or one recombinants. The estimated double recombination rate does add to our estimate of the distance between the more distant loci (A and C in the example). Trow's formula states that: cAC = cAB+cBC-2cABcBC



related articles

DNA Replication and DNA Transcription

DNA Replication and DN...

  • Basics
  • posted Date:2017 Sep, 16

Similarities between DNA Replication a...

read more
Human Chromosome Abnormalities

Human Chromosome Abnor...

  • Basics
  • posted Date:2017 Sep, 16

OverviewChromosome abnormalities include inversion, insertion, d...

read more
The 5' Cap and the Poly A Tail

The 5' Cap and the Pol...

  • Basics
  • posted Date:2017 Sep, 16

5' End CappingPost-t...

read more

Subscribe With Us For Daily Reading Lesson Materials