On Tuesday, June 7, 2016 at 9:19:52 AM UTC-7, Thomas Milton Tinney, Sr. wrote: > TAF, though you are highly learned, your statements and conclusions appear > to me to be intentionally and willfully misleading. The critical part of the sentence being 'to me'. First an aside: If you read the actual paper these stories are reporting on (I know, you don't actually read the scholarly papers on which you base your arguments, but one can hope), you will discover that there is nothing to see here. This was not a novel discovery. It was not dramatic. These two scientists simply wrote a review - they read a bunch of papers from the research literature and they summarized that research. All of the conclusions in their paper are not their own, they are just bringing together in one place the published conclusions of others. This hardly merits a press conference, let alone all of the over-hyped reporting in the popular media. The publicity department of the University of Western Australia should be congratulated for getting a non-finding reported as if it was an actual scientific discovery. Then they should be shot for getting a non-finding reported as if it was an actual scientific discovery. > Chromosome segregation is the process in eukaryotes by which two sister > chromatids formed as a consequence of DNA replication, . . . > https://en.wikipedia.org/wiki/Chromosome_segregation You are talking about mitosis here, where two identical chromosomes are separated into different cells. If this goes wrong and you end up with two identical copies in the same cell, how is that going to affect DNA testing? It's not because the answer is still the same - if some people have GATC and others have GAAC, then if a cell ends up with an extra copy of the same sequence, GAAC, and you test it, it will still show as GAAC. On the other hand, it could result in a cell missing the sequence all together and this will not report the other sequence - it will just produce a null result. A flaw in mitotic segregation does not change the identity of the DNA present, even if it changed the number of copies - it will give you the same result or a null result, not a different result. This specific report is about chromothripsis, the shattering of chromosomes that can occur in response to certain cellular insults. This usually results in cell death, but occasionally a cell patches back together all of the little pieces into a patchwork set of chromosomes, but here is the thing - all of the pieces are still the same, they are just strung together differently. Thus GATC is still GATC, even though it is now in a piece that is attached to chromosome 1 when it used to be on chromosome 15. When you do a SNP analysis, it will still show as GATC because the DNA analyses used in genetic and genealogic testing are micro-scale while the chromosomal rearrangements are macro-scale. But that is only half of the story. When this happens, it only happens in an occasional rare cell. Yes, that cell can give rise to a tumor, but it is just one cell. A cheek swab from someone who just smoked pot will still have 10s of thousands of normal cells for every 'shattered' one, so even if the shattering had an effect on DNA testing of that cell, which it doesn't, the signal from that cell would still be swamped by the 10,000 normal cells - you would never see the problem cell. When they talk about it possibly being passed down, they are referring to two entirely distinct phenomena, as again you would know had you read the paper. First, the shattering and rebuilding can theoretically happen in a gamete, in which case the progeny might have a rearranged chromosome, but all the chunks are there, just in different order, or are not there at all - again, the same result or a null result but not a changed result. They are also suggesting the possibility of epigenetic effects - these are chemical changes to the DNA that affect how it behaves in the cell, but do not affect its actual sequence - this will give you exactly the same result in DNA testing as unmodified DNA. So exactly which part of this is intentionally and willfully misleading? Do you have the expertise to know, or are you just the equivalent of the child who sticks his fingers in his ears and sings 'La, La, La' so as not to hear when someone else tries to tell them something they don't want to hear. taf

> So exactly which part of this is intentionally and willfully misleading? Do you have the expertise to know, or are you just the equivalent of the child who sticks his fingers in his ears and sings 'La, La, La' so as not to hear when someone else tries to tell them something they don't want to hear. > > taf TAF, I've been telling genetic genealogists about this conversation on the ISOGG Facebook group and you're become a celebrity over there! ---Nathan