Questions tagged [genetic-linkage]

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2answers
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Genetic linkage greater than 50 centimorgans

Classically, the linkage between two loci can be measured in centimorgans (cM), which represents the percent chance that these two loci will recombine an odd number of times (generating a recombinant ...
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4answers
888 views

What exactly is a centimorgan? [duplicate]

Centimorgan's aren't physical distances. The analogy that I could come up with is if you had an array with 10 items, A = [a, b, c, d, e, f ,g ,h ,i ,j, k] The ...
4
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1answer
129 views

Is complete genetic linkage possible?

Linkage is the tendency of genes on the same chromosome to remain together during the process of inheritance. Is it possible that two genes will remain linked generation after generation without any ...
4
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1answer
506 views

Is complete linkage found in all four chromosomes or only Y-chromosome of Drosophila? [duplicate]

Male Drosophila shows complete linkage. Is it observed for all four chromosomes or only the Y chromosome?
3
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1answer
5k views

recombination frequency problem

Three loci C, D and E are located on the same chromosome in this order. We found that the frequency of recombinants between C and D is 10% and that between D and E it is 20%. Assuming that ...
3
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1answer
81 views

What is the genetic distance where linkage can be ignored?

I heard several times that two SNPs, that have at least 1'000 nucleotides between them, can be seen as 'unlinked' due to frequent recombination events. I also once saw a paper showing a graph "degree ...
3
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0answers
374 views

A Genetic linkage problem [closed]

I have recently switched from electronics to computational biology. So having some hard time with my homeworks. Can someone guide me on this problem? Consider 6 genes A, B, C, D, E, F, G. Some ...
2
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1answer
46 views

Linkage between chromosomal loci and the Hardy-Weinberg principle

Referring to the Hardy-Weinberg principle, which is always stated with respect to a particular locus on the chromosome, if we observe that two different loci are either always together in Hardy-...
2
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1answer
3k views

What is the exact concept of “Repulsion” and “Coupling” (Genetics)?

From all sorts of books including standard books (like those by Tamarin, Griffith etc) as well as internet; I could not clear-up many things about "Repulsion" and "Coupling". Such as:- Is "Coupling" ...
2
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1answer
211 views

What test to apply to detect genomic signatures of selection?

I would like to ask you for your sugestions for selecting a test to detect signatures of selection in the following mouse model: We have three groups: animals exhibiting trait A, trait B and controls....
2
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1answer
310 views

Mitochondrial D-Loop

I know that the D-loop is a DNA complex in which the strands of double helix DNA molecule are separated for a stretch and held apart by a third strand of DNA. Usually, this third strand has a base ...
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2answers
85 views

Linked genes outcomes in offspring

This question is from a genetics session in my university: The test cross between a plant with smooth and yellow seeds and a plant with wrinkled and green seeds gives the following results: 140 ...
1
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1answer
56 views

Non-coding DNA correlation with rate of evolution

Non-coding DNA can be helpful in generating useful mutations that can go on to become new features/functionality of an organism. Non-coding DNA also indirectly reduces chances of mutation of useful/...
1
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1answer
479 views

Sex linked genes?

I am learning about genetics and sex-linked traits. All of the X-linked traits we have considered (eye colour in Drosophila, Duchene Muscular Dystrophy to name a couple)follow the rule that, a female ...
1
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1answer
282 views

Linkage Disequilibrium - What does it mean when D < 0?

What does it mean when you have a situation where your D<0?
1
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1answer
493 views

Linkage distance calculation

What is the map unit distance between L and S allele ? My working : If we take the normal ratio :9:3:3:1 , first one should be 9/16 = 0.5625 and then subtract 0.51 from it, we get 0.0525, similarly ...
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0answers
13 views

How does a neutral allele change relative to a nearby allele under selection?

Suppose I'm looking at a gene being selected against (A) that's decreasing at a rate ($\Delta$P). If there's a nearby allele that is neutral (B) am I correct to assume that B will decrease with A at a ...
1
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1answer
647 views

Why does allele linkage cause disproportionate phenotypic ratios? [closed]

I was learning about allele linkage in Biology class and I got confused by the resultant phenotypic ratios. Say you have a dihybrid cross BbGg x BbGg. The Punnett square would look like the ...
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0answers
51 views

Linkage disequilibrium D sign

Linkage disequilibrium D equals $D=x_{11}−p1⋅q1$ where: Haplotype Frequency $A_{1}B_{1} = x_{11}$ $A_{1}B_{2} = x_{12}$ $A_{2}B_{1} = x_{21}$ $A_{2}B_{2} ...
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2answers
31 views

Are SNPs always in linkage disequilibrium with other SNPs

Is it possible to have a SNP that is not found is be non-randomly associating with any other SNP?
0
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1answer
35 views

How to identify whether something is in linkage disequilibrium?

If the following loci indicated the presence of an SNP in flu strains, is Locus 2 and Locus 3, which are located 10 bp apart in linkage disequilibrium? "When alleles and molecular markers are ...
0
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1answer
2k views

Possible Genotypes — Linked Genes

Please consider the following question: Genes A and B are located on the same chromosome. If two individuals with the genotype shown below are crossed, which genotype could be formed? Let / ...
0
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1answer
208 views

How to decide if genes are linked in an unordered mapping problem?

From what I understand, if the tetrads resulting from a cross exhibit the same number of parental ditypes as there are nonparental ditypes, then the genes under consideration are said to be unlinked. ...
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0answers
15 views

Why is it more likely that EXACTLY one crossover will take place?

I'm studying genetic linkage and the recombination frequency calculation (that is estimated to be directly proportional to allele distance) consider that only one cross over will take place. I know ...
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0answers
65 views

Why do genetic testing companies (FTDNA,AncestryDNA,23andme) express DNA shared in centimorgans (cM) instead of in number of base pairs or in percent?

Expressing DNA shared in number of base pairs or in percent of total genome would be so much simpler and easier to understand for the customers. .
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0answers
104 views

Cis and trans linkage

Question: Two dominant non-allelic genes are 50map units apart, the linkage is: (A) Cis type (B) Trans Type (C) Complete (D) Absent/Incomplete My take: After a lot of ...
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0answers
83 views

Calculating gene separation -a genetics problem

I am really struggling with genetics. In particular, I have the following question Now I am OK with calculating the separation of genes in centrimorgans when I have data like so: But in the first ...
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0answers
501 views

Cut-off values for LD, LOD and D-prime as algorithmic input

I created an algorithm to generate SNPs for random people of different descents - based on HapMap data. While this works good, there is something else I want to take into consideration. So if a SNP ...