Re: New Markers: who's linked?
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In reply to:
New Markers: who's linked?
Elizabeth Ferguson 3/14/07
The problem with DYS389I and DYS389II has to do with the clumsy method of reporting them.If you subtract the first value from the second (II-I), you get DYS389B. It and DYS389I can then be treated like any other single-copy marker. Even though they are adjacent, they mutate independently. Many project websites are showing DYS389B to avoid confusing viewers.
http://www.smgf.org/pages/dys389.jspxhttp://www.smgf.org/pages/dys389.jspx
Multi-copy markers (those reported by most firms with lower-case letters attached to the name) are treated differently because of the inability of tests to distinguish the physical location associated with each value. See:
http://www.smgf.org/pages/duplicated_markers.jspxhttp://www.smgf.org/pages/duplicated_markers.jspx
In fact, a special test can distinguish copies of DYS385, making them equivalent to two single-copy markers. Another test can distinguish one of the copies of DYS464 for those in Haplogroup R1b, making it into a single-copymarker.
SMGF now shows matches by the genealogical method (each copy compared) in the boxes. However, it still uses the forensic method (composite markers for multiple copies) for reporting matches and TMRCA calculations. It doesn't make too much difference in determining relatedness in the time frames genealogists use. However, mutation patterns are very important, so the increased resolution of the genealogical method outweighs the slightly greater chance of error.
One big difference in using multi-copy markers is the possibility of conversion (recLOH) events. They are common enough that a surname project may encounter one. In extreme cases, they may cause close matches seemingly to break down upon upgrading. Anytime, there are close matches on single-copy markers and multiple mismatches and/or large genetic distances with duplicated values, a conversion should be considered.
http://www.dna-fingerprint.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=9&page=1http://www.dna-fingerprint.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=9&page=1
More Replies:
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Re: New Markers: who's linked?
Elizabeth Ferguson 3/15/07
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Re: New Markers: who's linked?
Elizabeth Ferguson 3/15/07
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Re: New Markers: who's linked?
Robert Stafford 3/15/07
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Re: New Markers: who's linked?
Elizabeth Ferguson 3/15/07
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Re: New Markers: who's linked?
Robert Stafford 3/16/07
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Re: New Markers: who's linked?
Elizabeth Ferguson 3/16/07
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Re: New Markers: who's linked?
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Re: New Markers: who's linked?
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Re: New Markers: who's linked?
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Re: New Markers: who's linked?