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  • 1798
    replied
    Originally posted by Parameswara View Post
    Female can't trace their maternal line through their X-Chromosome. Female got one X from her mother and one X from her father. X from her father will be (almost) identical with her father's X. But one X from her mother is recombination of 2 X that her mother had (one X from her maternal grandfather and one X from maternal grandmother).

    It doesn't mean the X she can trace her line through her X that she got from her father because her father got it from the paternal grandmother. The paternal grandmother has 2 X (from the mother of the paternal grandmother and the father of the paternal grandmother). And it already got recombined when it passed to the father. So the X-Chromosome just like autosomal, can detect multiply ancestry but can't point to paternal ancestry. Recombination is a random process. So we can't know which part will be pass to the next generation and which part will be vanish.

    Sorry, English is not my native language so I am afraid you are confuse to read my explanation. But at least I tried to explain.
    Everything is possible.
    Great mines discuss ideas.
    Average mines discuss events.
    Small mines discuss people.
    My English isn't great but you will understand I am Irish.

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  • Biblioteque
    replied
    Paramesware: Yes, that is easy to understand and very helpful. Thank you.

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  • Parameswara
    replied
    Originally posted by 1798 View Post
    A woman is female because she has two X chromosomes so both are female.One of the Xs would be very hard to trace because it recombines but the other doesn't. So the females can trace one of their maternal lines through the so called "male" X.
    I have 14 X matches and I have examined the SNPs that we match and none of them have combined alleles like the 1-22 chromosomes.
    My question is why doesn't someone put together an X tree for this female line? Does that make sense?
    Originally posted by 1798 View Post
    I have 17,509 X SNPs from Family Finder.
    AA 24%
    GG 26%
    TT 24%
    CC 26%
    From what I have read these are only a small percentage of the whole X chromosome but you say that they were recombined before they were passed on to me.
    Female can't trace their maternal line through their X-Chromosome. Female got one X from her mother and one X from her father. X from her father will be (almost) identical with her father's X. But one X from her mother is recombination of 2 X that her mother had (one X from her maternal grandfather and one X from maternal grandmother).

    It doesn't mean the X she can trace her line through her X that she got from her father because her father got it from the paternal grandmother. The paternal grandmother has 2 X (from the mother of the paternal grandmother and the father of the paternal grandmother). And it already got recombined when it passed to the father. So the X-Chromosome just like autosomal, can detect multiply ancestry but can't point to paternal ancestry. Recombination is a random process. So we can't know which part will be pass to the next generation and which part will be vanish.

    Sorry, English is not my native language so I am afraid you are confuse to read my explanation. But at least I tried to explain.

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  • 1798
    replied
    Originally posted by Kathy Johnston View Post
    Oh, OK. You can probably see that your X does not match anybody along the entire length. You must be seeing segments like you would on the autosomes then.

    Do you have multiple matches in the same place with other males? There are some men who match multiple men in the same place near the centromere and these regions don't crossover and break up very often.

    I have seen some interesting biogeographical patterns in some of the "kernels" that make up a match. So in that respect I think you are correct in asking why we don't follow the X back in time and mine for SNPs. I am one who actually believes in looking for these tiny phylogenetic trees even though these are hard to track because of mixing. In some regions on the X, it is productive.

    Some researchers use 100 SNP kernels to patch together a biogeographical prediction and can tell you in some cases where your ancestors came from getting it down to a local geographical area.

    We used to dissect out small sections from another company and compare raw data with each other in the old days when we did not have these chromosome browsers. It is still a great learning tool to do that to see the patterns. I don't know why we are not data-mining more markers and haplotypes from the X. Some people can't see the phylotrees for the forest. It is labor intensive so we really need computers to follow the migration paths of the nodal markers back in time. Maybe it is being done more than I realize.
    Thanks Kathy.I think in the future that the scientists will be able to trace some of the female lines through one X.I think that they will also be able to separate the 1-22 chromosome pairs and know which came from the male and female.
    The precision at birth that goes in to making a human is unbelievable.One or two minute mistakes can lead to serious health problems.

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  • Kathy Johnston
    replied
    Originally posted by 1798 View Post
    I have examined the 500 snps of each of the 14 matches.
    Oh, OK. You can probably see that your X does not match anybody along the entire length. You must be seeing segments like you would on the autosomes then.

    Do you have multiple matches in the same place with other males? There are some men who match multiple men in the same place near the centromere and these regions don't crossover and break up very often.

    I have seen some interesting biogeographical patterns in some of the "kernels" that make up a match. So in that respect I think you are correct in asking why we don't follow the X back in time and mine for SNPs. I am one who actually believes in looking for these tiny phylogenetic trees even though these are hard to track because of mixing. In some regions on the X, it is productive.

    Some researchers use 100 SNP kernels to patch together a biogeographical prediction and can tell you in some cases where your ancestors came from getting it down to a local geographical area.

    We used to dissect out small sections from another company and compare raw data with each other in the old days when we did not have these chromosome browsers. It is still a great learning tool to do that to see the patterns. I don't know why we are not data-mining more markers and haplotypes from the X. Some people can't see the phylotrees for the forest. It is labor intensive so we really need computers to follow the migration paths of the nodal markers back in time. Maybe it is being done more than I realize.

    Leave a comment:


  • 1798
    replied
    Originally posted by Kathy Johnston View Post
    I gather that you are a male so when you say combined alleles do you mean you are getting all homozygous (e.g. AA) instead of heterozygous (e.g. AG) results? That could also be causing some confusion. If all your alleles are the same such as AA, CC, GG, TT, TT etc. you need to subtract out one from each position for your one X chromosome. FTDNA lists these in duplicate. The software doesn't know you are a male even though it would be obvious to us by looking at the results. The chip sees only an A for position #1 so lists it as AA. For example, if no Gs fall into position #1 then you get AA. A female with two As will get AA but if she had one A and one G, the result would come out AG. Quite often women do have a long run of homozygous results on her two Xs but not the entire length. Males will show two alleles at each position in the FTDNA software but that is not real because he only has one X. Get rid of one of your alleles at each position.

    This may not be what you are referring to but I doubt that you have examined the raw data of all 14 of your matches. They would have to send that to you. I bet you have just examined your own results.

    Kathy
    I have examined the 500 snps of each of the 14 matches.

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  • Kathy Johnston
    replied
    Originally posted by 1798 View Post
    Thanks Matt.
    A woman is female because she has two X chromosomes so both are female.One of the Xs would be very hard to trace because it recombines but the other doesn't. So the females can trace one of their maternal lines through the so called "male" X.
    I have 14 X matches and I have examined the SNPs that we match and none of them have combined alleles like the 1-22 chromosomes.
    My question is why doesn't someone put together an X tree for this female line? Does that make sense?
    I gather that you are a male so when you say combined alleles do you mean you are getting all homozygous (e.g. AA) instead of heterozygous (e.g. AG) results? That could also be causing some confusion. If all your alleles are the same such as AA, CC, GG, TT, TT etc. you need to subtract out one from each position for your one X chromosome. FTDNA lists these in duplicate. The software doesn't know you are a male even though it would be obvious to us by looking at the results. The chip sees only an A for position #1 so lists it as AA. For example, if no Gs fall into position #1 then you get AA. A female with two As will get AA but if she had one A and one G, the result would come out AG. Quite often women do have a long run of homozygous results on her two Xs but not the entire length. Males will show two alleles at each position in the FTDNA software but that is not real because he only has one X. Get rid of one of your alleles at each position.

    This may not be what you are referring to but I doubt that you have examined the raw data of all 14 of your matches. They would have to send that to you. I bet you have just examined your own results.

    Kathy
    Last edited by Kathy Johnston; 10 April 2014, 01:03 PM.

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  • 1798
    replied
    Thanks Ann.
    I have 17,509 X SNPs from Family Finder.
    AA 24%
    GG 26%
    TT 24%
    CC 26%
    From what I have read these are only a small percentage of the whole X chromosome but you say that they were recombined before they were passed on to me.

    Leave a comment:


  • Ann Turner
    replied
    Originally posted by 1798 View Post
    Thanks Matt.
    A woman is female because she has two X chromosomes so both are female.One of the Xs would be very hard to trace because it recombines but the other doesn't. So the females can trace one of their maternal lines through the so called "male" X.
    I have 14 X matches and I have examined the SNPs that we match and none of them have combined alleles like the 1-22 chromosomes.
    My question is why doesn't someone put together an X tree for this female line? Does that make sense?
    You need to be able to follow the whole chromosome back for multiple generations. This is possible for the Y and mtDNA, because they don't break up.

    The X a woman receives from her father is indeed exactly like his X. It didn't break up for one generation. But he got his X from his mother, whose two X chromosomes underwent the recombination process to make his one X chromosome. Brothers will (almost always) have different X chromosomes. See this animation

    http://www.smgf.org/education/animat...hromosome.jspx

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  • LynCra
    replied
    Doesn´t make much sense to me, but then maybe I have misunderstood all of the literature I have read explaining the X-chromosome inheritance patterns

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  • 1798
    replied
    Originally posted by mkdexter View Post
    I'd be happy to help you understand this better but I do not know if you are actually asking for help. Some of the statements you have made about the X and Y do not really correlate to using the X chromosome to find related connections in the Family Finder test database.

    A large segment match (such as a block over 7cM) on the X chromosome between two individuals will indicate a relation, especially if one or both of them is a male. Since the X is not passed down from father to son, this creates a more unique inheritance pattern than that of the autosomal DNA and thus can be used in a more specific manner when two people have a Family Finder X chromosome match. That is why the X is unique, not because of its size or age or any other feature as far as DNA test matching is concerned.

    Now, if you were asking, it works like this: A male has one X chromosome that he inherited from his mother. That one X chromosome is his, but did come from his mother, meaning it is a male X chromosome from his maternal side. In reality, it is a copy of the first X chromosome he had which came from the egg supplied by the mother. I suppose we could disagree on whether it is a female or male X in this case yet in the case of his daughter, we would have to then say she has a male X and a female X. That is not really the way to describe any of it. This is how I would describe it.

    A male will have 23 pairs of chromosomes. In his 23rd pair will be a maternal X chromosome and a paternal Y chromosome, both making up the DNA of a male in this case. So while he has only one X chromosome, it is his, thus a male X chromosome from the maternal side and is paired with a Y chromosome from his paternal side.

    A female also has 23 pairs of chromosomes. In her 23rd pair will be a maternal X chromosome and a paternal X chromosome, both making up the DNA of a female in this case. So while she has two X chromosomes, they are both female X chromosomes, one from the paternal side, one from the maternal side.

    So there is a difference between where the chromosomes are inherited from but not all X chromosomes are female. In the male, they are male inherited from his maternal side, in a female, they are female inherited one from the maternal side, and one from the paternal side.

    Hope that helps.

    Matt.
    Thanks Matt.
    A woman is female because she has two X chromosomes so both are female.One of the Xs would be very hard to trace because it recombines but the other doesn't. So the females can trace one of their maternal lines through the so called "male" X.
    I have 14 X matches and I have examined the SNPs that we match and none of them have combined alleles like the 1-22 chromosomes.
    My question is why doesn't someone put together an X tree for this female line? Does that make sense?

    Leave a comment:


  • mkdexter
    replied
    Originally posted by 1798 View Post
    There really is no male X chromosome.Both X chromosomes are female.We men get an X from our mothers and pass it on to our daughters.The other X is passed on from female to female.
    The Y looks tiny compared to the X and both Xs are similar in size.All the other chromosomes from 1-22 are similar in size.
    SNPs happen over thousands of years so the X must be older than the Y.
    I'd be happy to help you understand this better but I do not know if you are actually asking for help. Some of the statements you have made about the X and Y do not really correlate to using the X chromosome to find related connections in the Family Finder test database.

    A large segment match (such as a block over 7cM) on the X chromosome between two individuals will indicate a relation, especially if one or both of them is a male. Since the X is not passed down from father to son, this creates a more unique inheritance pattern than that of the autosomal DNA and thus can be used in a more specific manner when two people have a Family Finder X chromosome match. That is why the X is unique, not because of its size or age or any other feature as far as DNA test matching is concerned.

    Now, if you were asking, it works like this: A male has one X chromosome that he inherited from his mother. That one X chromosome is his, but did come from his mother, meaning it is a male X chromosome from his maternal side. In reality, it is a copy of the first X chromosome he had which came from the egg supplied by the mother. I suppose we could disagree on whether it is a female or male X in this case yet in the case of his daughter, we would have to then say she has a male X and a female X. That is not really the way to describe any of it. This is how I would describe it.

    A male will have 23 pairs of chromosomes. In his 23rd pair will be a maternal X chromosome and a paternal Y chromosome, both making up the DNA of a male in this case. So while he has only one X chromosome, it is his, thus a male X chromosome from the maternal side and is paired with a Y chromosome from his paternal side.

    A female also has 23 pairs of chromosomes. In her 23rd pair will be a maternal X chromosome and a paternal X chromosome, both making up the DNA of a female in this case. So while she has two X chromosomes, they are both female X chromosomes, one from the paternal side, one from the maternal side.

    So there is a difference between where the chromosomes are inherited from but not all X chromosomes are female. In the male, they are male inherited from his maternal side, in a female, they are female inherited one from the maternal side, and one from the paternal side.

    Hope that helps.

    Matt.
    Last edited by mkdexter; 10 April 2014, 01:40 AM.

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  • KSDA
    replied
    Originally posted by 1798 View Post
    There really is no male X chromosome.Both X chromosomes are female.
    Just because the X chromosome doesn't recombine in males doesn't mean there is no male X chromosome.

    Originally posted by 1798 View Post
    We men get an X from our mothers and pass it on to our daughters.The other X is passed on from female to female.
    The other X isn't strictly passed from female to female. The X chromosome contributed to a daughter by the mother is a combination of that mother's own X chromosomes received from her mother and father.

    http://www.thegeneticgenealogist.com.../NewChart5.jpg

    Originally posted by 1798 View Post
    The Y looks tiny compared to the X and both Xs are similar in size.All the other chromosomes from 1-22 are similar in size.
    SNPs happen over thousands of years so the X must be older than the Y.
    The age of chromosomes isn't based on size. It's currently believed that the X and Y chromosomes diverged in mammals sometime between 160 and 300 million years ago, and they've existed concurrently since this time.

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  • 1798
    replied
    There really is no male X chromosome.Both X chromosomes are female.We men get an X from our mothers and pass it on to our daughters.The other X is passed on from female to female.
    The Y looks tiny compared to the X and both Xs are similar in size.All the other chromosomes from 1-22 are similar in size.
    SNPs happen over thousands of years so the X must be older than the Y.

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  • mkdexter
    replied
    Originally posted by 1798 View Post
    This is what I mean.The x chromosome has 155 million base pairs, longer than chromosome 8 but shorter than 7. There are more than 2 million SNPs discovered so far.

    The y chromosome has only 60 million base pairs, about the same as chr 19 and 20. It has fewer than 200K SNPs discovered.
    That doesn't make it less dominate than an X, just because it is smaller. I don't see the point.

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