One gene is known with a recombination frequency near 50%.
This means that it may have genes on the original chromosome but not the recombined chromosomes.
The one gene which has a recombination frequency near 50% is CFTR.
These genes are on the original chromosomes but not the recombined chromosomes.
CFTR is responsible for an autosomal recessive genetic disorders which can lead to serious health problems, including cystic fibrosis.
There are two genes known to have a recombination frequency near 50%, one from the MHC class
I region and the other from the MHC class II region.
These two genes may pass on different diseases to their offspring, because these genes are both involved in the defense mechanisms of their species.
A study done by Ellegren and Marck showed that there is a high rate of recombination between introns in exons.
When looking at amino acids on homologous proteins,
they found that recombination happens between conserved regions in one gene and non-conserved regions in another gene.
This shows that there is high likelihood for recombination to happen between similar regions of different proteins if they are close enough.
There are many implications that come along with recombination frequency.
The most important implication is that we are able to investigate specific regions of the genome.
Recombination frequency allows us to investigate genes that do not have high rates of recombination because they are furthest away from each other.
“Multiple genes with recombination frequencies near 50%”. Discoveries in Population Genetics. 3. p. 122–128.
Note that this is also the case for many other genes outside of recombination frequency,
but it is most notable in the MHC region, where there are many more alleles of interest.
This article incorporates public domain text from the reference.<br>
Articles:
Recombination frequency was proposed as a measure of gene diversity in population genetics theory by Stephen J. O’Brien and colleagues in 2008:
Although low recombination in the MHC region is surprising, it is not entirely unexpected.
There are genetic disorders that have multiple genes associated with them, and these genes have a high rate of recombination between themselves.
This is also seen in the MHC region. This article incorporates public domain text from the reference.
Recombination frequency
is also used to determine recombination events when looking at artificial populations, such as of microsatellites.
The following table shows the expected distribution of recombination frequency in different microsatellite lengths and meioses,
assuming that there is a fixed probability of recombination. Distributions are calculated on gene size (A) and number of alleles (N):
This rating curve shows the expected probability (from 0 to 1) that a gene will have a zero or 1 rate of recombination.
It increases with increasing length and decreasing meiosis. This data is generated using a population genetic program (DePastino, 2012).
This rating curve shows the expected probability that a gene will have no more than one recombination event.
It increases with increasing number of alleles and decreasing length. This data is generated using a population genetic program (DePastino, 2012).
This rating curve shows the expected probability that a gene will have no more than two recombination events.
It increases with increasing length, meiosis, and number of alleles.
This data is generated using a population genetic program.
The MHC region
has several alleles for many different diseases that are linked together by inheritance patterns involving a single gene.
If you have a gene on one of your chromosomes that is associated with a disease,
you have a 50% chance of passing that gene on to your offspring. This is why there are multiple alleles of the same gene in this region,
even though they have a high rate of recombination with each other.
This means that the MHC region has to be extra careful about the genes it places in the region because there are many diseases that it may pass on.
Also, all of these different alleles have differing functions and are encoded by very long regions of DNA.
Therefore, there is not much room in the MHC region for everything that is required by these genes as well as everything else in the genome.
The following table displays results from simulation experiments done by O’Brien et al.(2008). The values were statistically significant at the p<0.001 level.
Recombination frequency is associated with gene diversity in the MHC region
Note that this is also the case for many other genes outside of recombination frequency,
but it is most notable in the MHC region, where there are many more alleles of interest. which statement explains why the recombination frequency between two genes is always less than 50%?
Although low recombination in the MHC region is surprising, it is not entirely unexpected.
There are genetic disorders that have multiple genes associated with them, and these genes have a high rate of recombination between themselves.
This is also seen in the MHC region.