Sandy, Am I reading you correctly that you are saying that your DYS459=9,9 and DYS464=15,15,15,15 ? If so, then what is called a recLOH (recent loss of homogeneity) has occurred. What happens here is that an area where these markers lie is a palindrome, a loop back on itself, and one side copies to the other, loosing the original values. It is not uncommon for several markers to change at once, so DYS459 could change from 8,9 to 9,9 while DYS464 can change from 13,13,15,15 to 15,15,15,15 and even YCAII from 19, 23 to perhaps 23,23. BTW is your DYS463=25 ? This is another indication of Irish Type III membership. Dennis Wright <snip> Dennis, thanks for the information on your website. I just looked at and will study further what I found. The DYS markers values for 459 and 464 do fall within those you asked about. My cousin's 459a,b is 9, and the 464a,b is 15. Again, thanks to each of you for your valuable comments and suggestions ! Sandy Coulter ______________________________ PLEASE trim the amount you backquote in your replies to the minimum, especially if you subscribe in DIGEST mode. ------------------------------- To unsubscribe from the list, please send an email to Y-DNA-PROJECTS-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message

> Am I reading you correctly that you are saying that your > DYS459=9,9 and DYS464=15,15,15,15 ? If so, then what is > called a recLOH (recent loss of homogeneity) has > occurred. > > What happens here is that an area where these markers > lie is a palindrome, a loop back on itself, and one > side copies to the other, loosing the original values. > It is not uncommon for several markers to change at > once, so DYS459 could change from 8,9 to 9,9 while > DYS464 can change from 13,13,15,15 to 15,15,15,15 > and even YCAII from 19,23 to perhaps 23,23. <snip> I'm afraid "recLOH" does not stand for "recent loss of homogeneity." It stands for "recombinant loss of heterogeneity." It's called "recombinant" because it happens during the stage of cell division called "recombination." It's called a loss of heterogeneity because the markers are less diverse (more the same) as a result. The example you mention, where a recLOH happens at YCAIIa/b is one of the common ones. It results when, in a single mutation event, its values change from 19,23 to 23,23. The 19 allele hasn't added four copies, the 23 allele has written over the 19 allele. The other most common ones are, as you mention, with DYS464. The change from 13,13,15,15 to 15,15,15,15 happens in one mutation event when the two 15 alleles overwrite the two 13 alleles, however this results is a loss of heterogeneity and, thus, a gain in homogeneity. If DYS459a/b changes from 8,9 to 9,9, I don't know that you can necessarily invoke a recLOH. The change could simply be a single-step mutation in DYS459a. It could be a recLOH, but I don't know how you could tell the difference between it and a single-step mutation. The importance of recLOH's is that, despite causing a count difference of more than one, they represent one mutation event (i.e., a genetic distance of one). If you count each numerical difference as a single-step mutation, you will over-estimate the genetic distance between individuals. On the other hand... Just because two people are 13,13,15,15 and 15,15,15,15 doesn't mean they differ by a single recLOH event. They may simply not be closely related. You invoke a recLOH when two people are a very tight match on other markers, making it highly unlikely that the differences at DYS464 represent repeated single-step mutations on the same marker. Diana