Roper Y-Chromosome Project Family Connections
(www.roperld.com)

Go to Roper male-line Y-chromosome project web page.

Contents

• 25-Marker Results
  • Connections
  • Southern Roper Family
  • Northern Roper Family
  • Majority USA Roper Family Connections
    (A PDF file containing the known relationships among the MUR testees.)
  • West Virginia Roper Family
  • Raper Family
  • Probability Considerations
  • Majority USA Roper Family

Connections

Probability Considerations

I am indebted to William Alexander Roper, Jr. (mailto:william.roper@verizon.net) for the following thoughful analysis why we see so many single mutations among these participants:

After 10 generations, the MOST LIKELY marker comparison outcome for 12 markers is

• all markers the same (61.85%)
• 1 marker differs by 1 (29.75%)
• 2 markers differ by 1 (7.12%)
• 3 markers differ by 1 (1.13%)
• 4 markers differ by 1 (0.13%)
• 5 markers differ by 1 (0.01%).

So the most likely outcome after 10 generations is that all of the markers match, but the prospect of a 1-marker difference is actually pretty high. And the chance of a 2 marker deviation is certainly not inconceivable. Put another way, if you randomly selected 20 test subject all known to share a common ancestor 10 generations back, you would expect to have one of these 20 come up with a 2-marker deviation.

After 15 generations, the most likely marker comparison for 12 markers is:

• all markers the same (48.64%)
• 1 marker differs by 1(35.09%)
• 2 markers differ by 1 (12.62%)
• 3 markers differ by 1 (3.02%)
• 4 markers differ by 1 (0.54%)
• 5 markers differ by 1 (0.08%).

By the 22nd Generation, there is a crossover, and it is more likely that there will be a 1-marker difference (36.77%) than no difference (34.75%). Also, the prospect that 2 markers differ by 1 has grown to 19.42% and the chance of a 3-marker difference is more than remote at 6.82%. The 4-marker difference (1.79%) and 5-marker difference (0.38%) are still rather unlikely with the 12-Marker Test.

The expected distribution for the 25-marker test is even more interesting. After only 10 generations, a 1-marker difference (36.82%) is already more likely than no difference (36.75%). A 2-marker difference (18.41%) would not be unusual, and a 3-marker difference (6.13%) would be expected in a sample of twenty random test subjects known to be related with an MRCA ten generations back!

If one goes back 13 generations, a 1-marker difference (35.45%) would still be the most likely outcome, but a 2-marker difference (23.06%) is almost as likely as no difference (27.22%). Almost two (2) 3-marker differences (9.98%) would be expected in a twenty test subject sample. And the occasional appearance of a 4-marker difference (3.24%) would not be unusual in a sample this size or larger.

Looking back 16 generations, there is almost as great a chance of a two or more marker deviation (47.52%) in the 25-Marker test as there is for no difference (20.16%) and 1-marker difference (32.32%) combined. A 2-marker difference (25.87%) will not be unusual, nor will a 3-marker difference (13.79%) outcome. 4-marker differences (5.51%) would sometimes appear in a modest sample and 5-marker differences (1.76%) might occasionally appear where larger pools of test subjects known to be related through the male line within 16 generations were studied.

If one looks at the probabilities from a 23 generational vantage point, one finds that a 2-marker difference (26.54%) has supplanted a 1-marker difference (23.05%) as the most likely outcome. Both a 3-marker difference (20.35%) and a 4-marker difference (11.70%) are more likely than no difference (10.00%) after only 23 generations! In fact, a 3-marker difference is more than twice as likely as no difference. And the 5-marker difference (5.37%) is no longer remote and would be likely to appear in a modest sample of test subjects.

Majority USA Roper Family

The fact that the single-mutation cases, relative to the majority, all have a single mutation in different Y-chromosome locations illustrates the random nature of mutations. One of the identical sets of 12-markers is from the northern-USA Massachusetts Roper family (NJR). This indicates that there is a high probability that the 12 markers of the identical sets is the defining array of markers for the common ancestor in England of both these southern-USA and northern-USA Ropers. That defining 12-marker array for what I call the "Majority USA Roper Family" (MUR) and its common ancestor in England is:

Note that CFER & NJR are northern-USA Massachusetts Ropers and they have the same array of last 13 markers as many southern-USA Ropers. Thus we can conclude that their last 13 markers define, with high probability, the last 13-marker array for the common ancestor in England of both the southern-USA and northern-USA Ropers. Taking the defining original 12-marker array from above or what I call the "Majority USA Roper Family" (MUR), we get the 25-marker defining array for the "Majority USA Roper Family" and its common ancestor in England to be:

We do not know for sure where this common Roper ancestor lived in England and, of course, we do not know his given names. Any Roper male who wants to determine if he is in the MUR can find out by having his 25 markers measured; if he is in the family his markers will agree with this marker set or only differ by one or two mutations.

Note that, since the first 12 markers for NJR are the same as for the Majority USA Roper family (MUR) and the last 13 markers for CFER are the same as for MUR and NJR and CFER are known to descend from Ephraim Roper Jr (1687MA), there is a high probability that Ephraim Roper Jr (1687MA) has the same 25 markers as the MUR. For the first time in this Roper Y-chromosome project, the set of 25 markers has been determined for a common early ancestor but not for all his descendants. Similar arguments hold for Meredith Roper (c1735VA), if the descendancy is as shown. (I thank Bill Roper [WAR] for pointing this out to me.)

Also, note that the 25 markers for David Roper(1744VA) appear to be the MUR markers except for a single relative mutation +1 at DYS458.

The single mutations, relative to the MUR markers, of the different MUR family branches define the branches. Some different branches of MUR are defined by the following single mutations:

Donald Keith Roper has the same DYS458(+1) relative mutation to MUR as does William Alexander Roper, Jr., plus another relative mutation: DYS439(-1).
James Everett Roper, Jr. has the same DYS458(-) relative mutation to MUR as does Carl Stern Roper, plus another relative mutation: DYS390(+).
Gary Lee Roper has the same DYS459b(+) relative mutation to MUR as does Robert Preston Roper, plus another relative mutation: DYS458(+); and he also has the same DYS458(+) relative mutation to MUR as does William Alexander Roper, Jr., plus another relative mutation: DYS450b(+); that is, he is in a genetic bridge between GLR and WAR.

A way to visualize these connections is by a phylogenetic network (http://www.fluxus-engineering.com/sharenet.htm):

Note that JER appears to be in the CSR branch of the family, DKR appears to be in the WAR branch and GLR genetically bridges the WAR and RPD branches. We are seeing some complex structure coming out of single mutations between MUR family members. Note that, although JER and DKR are four relative mutations apart, they are part of the same, probably ancient, Roper family. I think, if we can get enough distantly related cousins to be tested, we will get a complex linking of many cousins, some of which on the genetic periphery will have several relative mutations.

Go to Roper male-line Y-chromosome project web page.

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