Linkage and recombination

In summary, the conversation discusses the lack of recombination in the F1 generation and how it is affected by the parental chromosomes being homozygous. It is explained that while there may be recombination in the founders, it does not change the information content of their genomes. The specific example of inbred fruit flies is given, where physical recombination in the parental germ lines would not yield any difference in the offspring. However, in the F1 generation, which has one paternal and one maternal copy of each chromosome, recombinations between these chromosomes can occur and cause their progeny to be different and recombinant with respect to the original two lines. It is noted that this is a specific situation and highly inbred lines are usually only
  • #1
gracy
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upload_2014-11-28_21-18-3.png
my question is why there is not any recombination in F1 generation?
 
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  • #2
If you took the parental chromosomes and recombined them, what would they look like?
 
  • #3
In other words, there is recombination in the founders, but since they are homozygous (according to the figure shown), the recombination doesn't change the information content of their genomes so it doesn't "look like" any recombination happened. Physically it did, recombination is probably physically required for proper chromosome segregation during meiosis. The except is the X and Y, for which there is no recombination because they are different chromosomes. In humans however there is a bit of DNA including a handful of protein-coding genes that is shared betwenthe X and Y chromosomes, so there is recombination. I'm not sure if that happens in Drosophila, which is the example given.
 
  • #4
mes314159 said:
In other words, there is recombination in the founders, but since they are homozygous (according to the figure shown), the recombination doesn't change the information content of their genomes so it doesn't "look like" any recombination happened.
I think recombination occurs between one chromosome of mother and one of father (i.e homologous)so no matter homozygous or not there should be recombinations.as in this video at time 5:08 to 5:20.
 
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  • #5
In the original figure in this thread, an example was shown of fruit flies that were already highly inbred, so the father and mother were each mostly homozygous, at least on the X chromosome. In that specific example, physical recombinantions in the parental germ lines would not yield any difference in the offspring. The F1 generation however, which has one paternal and one maternal copy of each chromosome (two different X-chromosomes for F1 females), recombinations between these chromosomes in the F1 germ line will cause THEIR progeny to be different and recombinant with respect to the original two lines. This is a very specific situation, and highly inbred lines are usually only found in laboratory animals like mice, flies or fish that have been inbred for many generations by crossing brothers and sisters. Animals seem to be ok doing this, at least in the lab. The practice is not unknown even in humans (as with the ancient egyptian pharaohs who supposedly often married their sisters), although it also leads to geneticproblems in the children of such matings - not guaranteed, but more likely.
 
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Likes gracy
  • #6
mes314159 said:
In the original figure in this thread, an example was shown of fruit flies that were already highly inbred, so the father and mother were each mostly homozygous, at least on the X chromosome. In that specific example, physical recombinantions in the parental germ lines would not yield any difference in the offspring. The F1 generation however, which has one paternal and one maternal copy of each chromosome (two different X-chromosomes for F1 females), recombinations between these chromosomes in the F1 germ line will cause THEIR progeny to be different and recombinant with respect to the original two lines. This is a very specific situation, and highly inbred lines are usually only found in laboratory animals like mice, flies or fish that have been inbred for many generations by crossing brothers and sisters. Animals seem to be ok doing this, at least in the lab. The practice is not unknown even in humans (as with the ancient egyptian pharaohs who supposedly often married their sisters), although it also leads to geneticproblems in the children of such matings - not guaranteed, but more likely.
thanks.
 
  • #7
mes314159 said:
In the original figure in this thread, an example was shown of fruit flies that were already highly inbred, so the father and mother were each mostly homozygous, at least on the X chromosome. In that specific example, physical recombinantions in the parental germ lines would not yield any difference in the offspring. The F1 generation however, which has one paternal and one maternal copy of each chromosome (two different X-chromosomes for F1 females), recombinations between these chromosomes in the F1 germ line will cause THEIR progeny to be different and recombinant with respect to the original two lines. This is a very specific situation, and highly inbred lines are usually only found in laboratory animals like mice, flies or fish that have been inbred for many generations by crossing brothers and sisters. Animals seem to be ok doing this, at least in the lab. The practice is not unknown even in humans (as with the ancient egyptian pharaohs who supposedly often married their sisters), although it also leads to geneticproblems in the children of such matings - not guaranteed, but more likely.[/QUOTE
gracy said:
View attachment 75905my question is of F1 generation
 
  • #8
mes314159 said:
In the original figure in this thread, an example was shown of fruit flies that were already highly inbred, so the father and mother were each mostly homozygous, at least on the X chromosome. In that specific example, physical recombinantions in the parental germ lines would not yield any difference in the offspring. The F1 generation however, which has one paternal and one maternal copy of each chromosome (two different X-chromosomes for F1 females), recombinations between these chromosomes in the F1 germ line will cause THEIR progeny to be different and recombinant with respect to the original two lines. This is a very specific situation, and highly inbred lines are usually only found in laboratory animals like mice, flies or fish that have been inbred for many generations by crossing brothers and sisters. Animals seem to be ok doing this, at least in the lab. The practice is not unknown even in humans (as with the ancient egyptian pharaohs who supposedly often married their sisters), although it also leads to geneticproblems in the children of such matings - not guaranteed, but more likely.
where are Gametes of F1 generation in this picture ?I am confused which picture refers to what for eg. which picture refers to Gametes of F1 generation and which picture refers to F2 generation?
 

1. What is linkage and recombination?

Linkage and recombination are two related genetic phenomena that occur during the process of meiosis, specifically during the formation of gametes. Linkage refers to the tendency of genes that are located close together on the same chromosome to be inherited together, rather than independently. Recombination, also known as crossing over, is the exchange of genetic material between homologous chromosomes during meiosis, resulting in new combinations of alleles.

2. How does linkage affect the inheritance of traits?

Linkage can affect the inheritance of traits by preventing the independent assortment of genes. This means that genes that are closely linked on the same chromosome are more likely to be inherited together and less likely to be separated by recombination. As a result, certain traits may be passed down together, rather than independently, if they are located close to each other on a chromosome.

3. What factors influence the frequency of recombination?

The frequency of recombination is influenced by several factors, including the distance between genes, the location of genes on the chromosome, and the presence of crossing over hotspots. Genes that are farther apart on a chromosome are more likely to undergo recombination, while genes that are closer together are less likely to recombine due to their close physical proximity.

4. Can linkage and recombination be used to map the location of genes?

Yes, linkage and recombination can be used to create genetic maps that show the relative location of genes on a chromosome. By analyzing the frequency of recombination between genes, scientists can determine the distance between them and create a map of their relative positions on the chromosome. This information is useful in understanding genetic diseases and inheritance patterns.

5. How does genetic linkage differ from genetic inheritance?

Genetic linkage refers to the tendency of genes to be inherited together, while genetic inheritance refers to the passing of traits from parents to offspring. Linkage is a physical phenomenon that occurs during meiosis, while inheritance is a broader concept that encompasses both genetic and environmental factors that influence the expression of traits.

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