For use in trying to identify patterns in markers that may shed light upon the closeness and timing of relationships, this website posts a spreadsheet that compiles: (1) publicly available Y-DNA results for R1a1a Ashkenazi Levite men who have done Y-DNA testing and have tested at least 37 markers (and for some such men who have tested only to 25 markers); and (2) information concerning mutation rates of those markers for the population as a whole and the frequency of each marker value among the R1a1a Ashkenazi Levites for whom test results are included.
The spreadsheet provides information concerning test results for each man. The spreadsheet uses blue highlighting to identify marker values that are below the R1a1a Ashkenazi Levite mode, and red highlighting to identify markers that are above the R1a1a Ashkenazi Levite mode, with darker highlighting indicating, in gradation, the number of steps by which those markers differ from the R1a1a Ashkenazi Levite mode.
The spreadsheet provides three sets of data concerning Y-DNA mutation rates on a marker-by-marker basis. The first two sets of data concern general mutation rates for each marker: (1) mutation rates for the first 37 markers, as reported several years ago by Family Tree DNA; and (2) mutation rates for most of the 111 markers that are not palindromic, as reported in a 2010 article compiling information from 29 studies of Y-DNA mutation rates. The third set of data tabulates the test results for the R1a1a Ashkenazi Levites for whom test results are reported to determine the frequency with which men reporting test results deviate from the R1a1a Ashkenazi Levite mode on each marker, and the number of steps and direction by which they deviate in the aggregate from the mode. The same information is also posted here.
The spreadsheet contains the results for most men identified as R1a1a Ashkenazi Levites in their publicly available test results whose Y-DNA 37, Y-DNA 67, or Y-DNA 111 test results were posted on any of eight Family Tree DNA projects as of December 14, 2012. Since then, additional results have been added for men whose reports were not posted on those projects or who have tested or upgraded more recently, including results posted on the Semargl website for R1a1a Ashkenazi Levites (under the designation R1a-Z93+, Z94+, Z2124+, Z2122+, F1345+, CTS6+ (AL)). The spreadsheet also contains a handful of results that have not been publicly posted, with the consent of the tested men.
The spreadsheet currently contains the test results for perhaps 80%, and 90% respectively, of the identified R1a1a Ashkenazi Levites with public profiles who have done Y-DNA 67 or Y-DNA 111 testing, respectively, through Family Tree DNA. The spreadsheet contains the test results for perhaps 50% of the identified R1a1a Ashkenazi Levites with public profiles who have done Y-DNA 37 testing through Family Tree DNA.
Because of the relatively large number of test results included on the spreadsheet, it is unlikely that adding the missing test results would have a marked effect on the calculations concerning the frequency of deviations from the R1a1a Ashkenazi Levite mode on markers 1 through 67; because the sample size on markers 68 through 111 is currently more limited, additional test results may significantly change the calculations concerning the frequency of mutations on certain markers. Furthermore, some of the missing test results are likely to be very significant when determining which men are the most closely related to each other, when a line’s individual mutations likely occurred, and whether mutations are likely to have occurred independently of each other. We welcome information concerning missing (or incorrectly reported) test results.
Hints for Using the Spreadsheet
Following are some suggestions for using the sortable spreadsheet to analyze your matches. A sample analysis, using this methodology, is also posted on this website.
Sorting the Spreadsheet to Your Closest Matches
To determine which markers are the most significant for genealogical purposes, it will be helpful to compare your Y-DNA results to those of your closest matches.
In order to sort the spreadsheet so that you can compare your results to those of selected men, you can type in the same number or letter (e.g., “1” or “A”) in one of the “Steps at __” columns for each of the men whose results you want to compare. If you then sort that column by smallest to largest, the selected results will appear at the top of the spreadsheet.
One systematic way to compare your closest matches is to enter on the spreadsheet, under the columns “Steps at 37,” “Steps at 67,” or “Steps at 111,” the number of steps between you and those matches at 37, 67, or 111 markers.
The Steps to Matches spreadsheet posted on the website, used in conjunction with the sortable spreadsheet, makes it easy to sort the sortable spreadsheet to your closest matches:
1. Confirm that the Y-Utility spreadsheet and the sortable spreadsheet bear the same date.
2. Confirm that the sortable spreadsheet is sorted in the order in which it is posted on the website (i.e., 111-marker matches listed by ascending kit numbers, followed by 67-marker matches listed in the same order, and so on).
3. On the Y-Utility spreadsheet, go to the spreadsheet page reporting genetic distance at 111 markers, 67 markers, or 37 markers, and find the column bearing the name of the man whose results you wish to analyze.
4. Copy the column of numbers for that man (starting at line 3; you should not copy the blue number, which reflects the mode) and paste that column into the appropriate column of the sortable spreadsheet (i.e., “Steps at 111,” “Steps at 67,” or “Steps at 37”).
5. On the sortable spreadsheet, find the row in that column for that man and change the number in that column to zero from 111, 67, or 37.
6. Go to the top number in that column and sort that column, smallest to largest. This will show you all of that man’s matches at 111 markers, 67 markers, or 37 markers, sorted in order of genetic steps.
If there is no Y-Utility spreadsheet matching the sortable spreadsheet, the same sort of analysis can be performed, but it will take considerably more effort.
While it is possible to count the number of steps manually, it is now more difficult to do so because Family Tree DNA has changed the way that it calculates genetic distance (by decreasing the significance of differences in palindromic markers and null values). Accordingly, it is easier to have genetic distance calculated for you by a website. Family Tree DNA’s Y-DNA match page provides that information for 12, 25, 37, 67, and 111 markers (but only for your closest matches), and YSearch also provides the same information for those matches who have posted their data on that website.
If you’ve tested to 67 or 111 markers and you’ve posted your results on a Family Tree DNA project or YSearch, you can search for your surname or kit number on the Semargl website. If your marker values are posted on that website, you will be able to identify all of your matches at 67 markers and 111 markers who have also posted their results on a Family Tree DNA project or YSearch (not just your closest matches); that website will also color-code your matches’ test results so that you can easily see the markers where your matches’ values differ from your values.
After you’ve obtained information concerning genetic distance, you can enter the number of steps for each match on the spreadsheet under the columns “Steps at 37,” “Steps at 67,” or “Steps at 111,” as appropriate. You can then sort the spreadsheet by smallest to largest based upon that column, which will leave your closest matches clustered together at the top rows of the spreadsheet.
Looking for Patterns in Your Closest Matches
Sorting the spreadsheet according to genetic distance will be of most use to those with a significant number of deviations from the R1a1a Ashkenazi Levite mode; such men will have a relatively small number of close matches, who will be more likely to share deviations of probable genealogical significance. The method is less likely to work – especially at 37 markers – for men who are close to the R1a1a Ashkenazi Levite mode; those men will have many matches, and many of their closest matches will deviate from the mode on different markers; however, if such a man has a deviation from the mode on a slow-mutating marker, this method may be helpful in identifying his closest relatives.
The following may be of assistance in analyzing deviations from the R1a1a Ashkenazi Levite mode:
1. Deviations Shared by All of Your Closest Matches. The spreadsheet may show some markers where you and your closest matches share a deviation from the R1a1a Ashkenazi Levite mode. These markers are likely to be genealogically significant, i.e., they likely evidence a mutation that occurred long enough ago to delineate a branch of the family tree, especially on slow- or medium-mutating markers.
2. Deviations Shared by Some of Your Closest Matches. The spreadsheet may show some markers where you and some – but not all – of your closest matches share a deviation from the R1a1a Ashkenazi Levite mode. These markers are likely to be genealogically significant on a more recent scale, i.e., they likely reflect a mutation that occurred more recently than the mutations shared by all of your closest matches, and therefore may evidence a more recent branch of the family tree, especially on slow- or medium-mutating markers.
3. Deviations Not Shared by Your Closest Matches. A deviation that is not shared by any of your closest matches may reflect a mutation that occurred quite recently – perhaps in the past several generations – and that therefore should be given less weight in estimating how close your relationship is to your matches. Similarly, if one of your closest matches has a deviation not shared by your other closest matches, that deviation should be given less weight in estimating how close your relationship is.
4. Single Deviation. A single deviation – even a rare one – may have arisen from independent mutations; depending upon the rarity of mutations, men generally must share two or three deviations from the R1a1a Ashkenazi Levite mode in order for one to conclude, with a reasonable degree of certainty, that the shared deviations are genealogically significant.
5. Shared Deviations of Multiple Steps. With the exception of certain palindromic markers (discussed in more detail below), a deviation of multiple steps reflects two separate, independent mutations. Thus, for example, a shared deviation of two steps on a single marker is as genealogically significant as a shared deviation of one step on two markers.
Looking for More Distant Matches
After you’ve identified the marker or markers on which you and your closest matches deviate most significantly from the R1a1a Ashkenazi Levite mode, you can look for other men who, although not among your closest matches (and, perhaps, too far in genetic distance to be identified as matches by Family Tree DNA), share the same deviations on the same marker or markers. You can find those deviations by sight, but it will generally be easier to sort the spreadsheet by smallest to largest (or largest to smallest) based upon that marker. If you identify more than one deviation that is shared by your closest matches, you can use Excel’s custom sort function to more easily identify those men who share both of those deviations.
1. Distant Matches Sharing Multiple Deviations. If a more distant match shares a deviation with you on a significant marker and also shares deviations with you on other markers, that match is likely to share a common direct male ancestor with you, but such ancestor is likely to be more remote than the men identified by Family Tree DNA as matches.
2. Distant Matches Sharing a Single Unusual Deviation. If a more distant match shares a deviation with you on one marker but not on other markers, that match’s mutation is more likely to have arisen independently from the mutation on your line, and therefore is less likely to be genealogical significant.
3. Multiple Step Deviations. Sometime, you or a match – especially in the case of more distant matches – will have a marker deviating by more than one step from the R1a1a Ashkenazi Levite mode. Such two-step or three-step deviations from the R1a1a Ashkenazi Levite mode may be useful in determining the order in which mutations occurred, since such a deviation will generally reflect more than one mutation in that marker occurring across generations. Thus, a match with a two-marker deviation from the R1a1a Ashkenazi Levite mode is generally more likely to share a more recent direct male ancestor with a match with a one-marker deviation from the mode than with a match who is at the mode on that marker.
Where men have other genealogically significant matches, a two-step difference on a marker where one man is one step above the R1a1a Ashkenazi Levite mode and another man is one step below the mode may indicate that both men’s lines deviated from the mode on that marker (in different directions) after their shared ancestor had the other mutations that the two men share.
Looking for Y-DNA 37 Matches Who May be Closely Related.
Using the same methods discussed above, you can look for Y-DNA 37 matches who share with you one (or, preferably, several) deviations from the R1a1a Ashkenazi Levite mode. Those matches are more likely to be close matches for you. Testing those matches to 67 markers or 111 markers can confirm – or disprove – a relatively close relationship.
1. Mutation Rates. As shown here, some markers mutate far more frequently than other markers in the population at large, and some deviations from the R1a1a Ashkenazi Levite mode are more common than others. Generally speaking, a single mutation in a fast-mutating marker will be of less genealogical significance than a single mutation in a slow-mutating marker. As discussed above, however, a mutation that is unique or nearly unique among the test results appearing on the spreadsheet is less likely to be of genealogical significance, regardless of the frequency with which that marker mutates.
Note that the fact that a large percentage of R1a1a Ashkenazi Levites differ from the mode on a particular marker can mean either that: (1) the marker mutates relatively frequently; or (2) the marker mutated once many years ago and therefore reflects a major branch of the R1a1a Ashkenazi Levite family tree.
Out of the 111 markers tested by FTDNA as part of its standard testing, there are only 10 markers where: (1) at least 5% of tested R1a1a Ashkenazi Levites have a marker value differing from the R1a1a Ashkenazi Levite mode; and (2) there is a second group of at least 5% of tested R1a1a Ashkenazi Levites who have a marker value that differs both from the R1a1a Ashkenazi Levite mode and from the marker value of the first group of R1a1a Ashkenazi Levites. Those 10 markers (DYS449, DYS607, DYS576, DYS570, CDYa, CDYb, DYS710, DYS714, DYS712, and DYS650) are all within the top 20 markers on which there is the most deviation from the mode among R1a1a Ashkenazi Levites. Given this evidence that these markers have mutated more frequently, dissimilarities in these markers may sometimes be entitled to less weight than dissimilarity in markers that show less of a tendency towards mutation.
2. Back Mutations. In most if not all cases, a Y-DNA marker is equally likely to mutate by adding or subtracting a STR. Thus, a marker that deviates by one step from the R1a1a Ashkenazi Levite mode is equally likely to mutate to two steps away from the mode or, in what is known as a back mutation, back to the mode. A back mutation creates complications in determining how close a relationship is, the order in which mutations occurred, and the relative times at which various matches’ lines branched off from the family tree.
3. Lack of Deviations from the R1a1a Ashkenazi Levite Mode. This analysis is rendered considerably more difficult for those men who have relatively few deviations from the R1a1a Ashkenazi Levite mode. When two men with few deviations from the R1a1a Ashkenazi Levite mode closely match each other, it could reflect a relatively recent common direct male ancestor, but it may also reflect two more distantly related lines with few or no mutations over the past thousand years.
Men who are at or near the R1a1a Ashkenazi Levite mode at 37 markers or 67 markers may need to upgrade their test results to 67 markers or 111 markers in order to find deviations that could help them identify their closest matches. Men who are at or near the R1a1a Ashkenazi Levite mode at 111 markers may need to have custom testing performed – such as the DYF399X test or Y-DNA SNP testing – in order to determine which of their matches are most likely to share a recent direct male ancestor.
4. Recent Mutations. Because Y-DNA mutations occur randomly, there will be a substantial number of men whose direct male lines have undergone mutations in the last several generations. In such cases, those mutations likely would not be shared with most if not all of the man’s closest matches. As a result of such recent mutations, the man may not have many Y-DNA matches on Family Tree DNA, especially at 37 markers, where a deviation of one or two additional steps will take many matches out of range.
If you are fortunate enough to have test results from a distant cousin known through a paper trail to share a common direct male ancestor – the more distant the better – you should be able to determine which mutations have occurred in each of your lines since the time of that shared male ancestor (although the possibility of back mutations will make it difficult to be certain as to the direction of each mutation, unless the original marker value may be ascertained by analyzing the marker values of other close matches).
5. Differences in Reproduction and Survival Rates. For a variety of reasons (putting aside mutations), the current number of living men with certain marker values will not be representative of the number of men who had those marker values hundreds of years ago. All other things being equal, a man who had many sons who lived to maturity and fathered children of their own will have far more descendants sharing his Y-DNA than would a man who had fewer sons who lived to maturity and fathered children of their own. Conversely, catastrophes including the Holocaust, pogroms, and disease doubtlessly decimated or wiped out entirely some men’s direct Y-DNA lines. Accordingly, deviations that are common (or rare) in the men whose test results appear on the spreadsheet may or may not have been common (or rare) several hundred years ago.
6. Undersampling. Because the pool of men who undergo Y-DNA testing and make their results publicly available is self-selected, it is possible that some deviations that appear to be unusual among R1a1a Ashkenazi Levites are not in fact unusual among them. As a result, deviations that currently appear to be unique and therefore of little genealogical significance may later be discovered to be more common, and therefore to reflect a more distant branching of the family tree.
7. Oversampling. Some apparent clusters in Y-DNA results may reflect the fact that closely related men are more likely to have undergone Y-DNA testing to determine how closely they are related (especially at 67 and 111 markers). In those circumstances – which will be obvious where the men identify the same ancestor and suspected where the men have the same surname, but will otherwise not be apparent – the fact that a number of matches share an unusual deviation from the R1a1a Ashkenazi Levite mode will be less significant for broader genealogical purposes than when the same deviation is shared by the same number of men without a known genealogical connection.
8. Palindromic Mutations. Due to a type of mutation known as Recombinational Loss of Heterozygosity (“RecLOH”), in which one gene on a palindromic marker overwrites another gene, there are some markers (including, at least, DYS459, DYS464, and CDY) where a single mutation can result in a marker changing by more than one number. Furthermore, because DYS459 (which contains two markers), DYS464 (which generally contains four markers), and CDY (which contains two markers) are located close to one another on the Y chromosome, a single mutation can result in simultaneous changes to more than one of those markers. Accordingly, mutations on the palindromic markers may make matches seem to be more distant than they are.
Using the Spreadsheet to Identify Branches in the R1a1a Ashkenazi Levite Family Tree
Based upon the frequency with which markers mutate and the patterns of marker values among groups of men evidenced on the sortable spreadsheet, it appears that some marker values may delineate distinct branches in the R1a1a Ashkenazi Levite family tree. Because mutations can occur independently, however, it is possible that some men or groups of men with marker values that appear to delineate such branches may in fact belong to a different branch.
1. DYS650. DYS650 is the marker on markers 68 through 111 that appears to be the most likely to delineate an early branch in the R1a1a Ashkenazi Levite family tree. Currently, about 60% of R1a1a Ashkenazi Levites who have tested to 111 markers have the mode of DYS650=20, while the remaining 40% have DYS650<20 (including several men with DYS650=17). (General mutation frequency rates for DYS650 have not been reported.)
Given the facts that (1) as discussed below, DYS650<20 is shared by men with both DYS537=10 and DYS537=11, (2) some men have DYS650<19, and (3) Janzen spreadsheets calculate that the time to an MRCA for the cohort of men with DYS650<20 is four centuries longer than the time to an MRCA for the cohort of men with DYS650=20, it appears most likely that: (a) the original R1a1a Ashkenazi Levite mode was DYS650=19; and (b) the mutation on DYS650 occurred before the mutation on DYS537.
It may be the case that DYS650=19 was the original marker value; if so, the fact that DYS650=20 is the mode would indicate that this branch of the R1a1a Ashkenazi Levite family tree, although more recent, has been more successful than the earlier branches.
2. DYS537. DYS537, on markers 38 through 67, appears to delineate an early branch in the R1a1a Ashkenazi Levite family tree. Currently, about 55% of tested men have the mode of DYS537=12, while about 45% of tested men have DYS537=11. While there have presumably been independent mutations of DYS537 in the R1a1a Ashkenazi Levite population, independent mutations are likely uncommon because: (1) DYS537 is a slow-mutating marker (mutating 0.0124% per generation, according to Burgarella et al.); and (2) all of the men with DYS537=12 who have tested to 111 markers have DYS650=20 (with one immaterial exception), while some of the men with DYS537=11 who have tested to 111 markers have DYS650<20 but others have DYS650=20.
3. DYS459b. Michał Milewski, Administrator of the FTDNA R1a1 and Subclades Y-DNA project, has identified DYS459b, on markers 13 through 25, as a marker that is likely to delineate an early branch in the R1a1a Ashkenazi Levite family tree. DYS459b mutates slowly. Currently, about 52% of tested men have the mode of DYS459b=10, while about 46% of tested men have DYS459b=11.
4. DYS456, DYS607, DYS576, and DYS570. DYS456, DYS607, DYS576, and DYS570 are fast-mutating markers, reported by Family Tree DNA adjacent to each other in markers 27 through 37, that have a broader range than most other markers among R1a1a Ashkenazi Levites. Patterns on these markers may often be used to identify men’s closest matches and to draw inferences concerning the order in which mutations likely occurred, providing insight into more recent branches in the family tree. Conversely, differences on one or two of these markers may not rule out a relatively recent shared direct male ancestor.
Furthermore, multiple variances from the mode on DYS607, DYS576, and DYS570 appear to be associated with DYS650<20. DYS576>20, in particular, appears to be associated with two well-defined subclusters of R1a1a Ashkenazi Levites who also have DYS650<20 and DYS537=11; men with these marker values likely belong to pre-Horovice branches of R1a1a Ashkenazi Levites, i.e., their shared MRCA with the Horowitz rabbinical family likely pre-dates that family's move to Horovice in the 1470s.
Using information about certain matches, you may be able to draw some conclusions about the closeness of your matches and the time when various lines of your family tree branched off from one another.
1. Known Family Lines. If (1) you have traced your direct male line back to, e.g., 1800, (2) your match has traced his direct male line back to, e.g., 1800, and (3) the two of you have not identified a shared direct male ancestor, you will know (absent an adoption or another event disrupting the known line of direct male descent) that your common direct male ancestor pre-dates 1800. That would mean that any deviations from the R1a1a Ashkenazi Levite mode that you share with your match probably also pre-date 1800.
2. Geography. If you know that either your direct male line or your match’s direct male line moved to some geographically remote location in the past such that there was no possibility that the two lines could have shared a common direct male ancestor since that move – e.g., if your direct male ancestor moved to the Americas, Australia, or, perhaps, the United Kingdom while your match’s direct male line remained in continental Europe – you will know (absent an adoption or another event disrupting the known line of direct male descent) that the common direct male ancestor pre-dates the date of the move.
3. Surnames. If you and your match share a surname, the odds are good that your common direct male ancestor lived during the period after Jews adopted surnames. The period when Jews adopted surnames varied greatly, depending largely upon the area within the family lived.
The Horowitz Rabbinical Family
As noted here, the Horowitz rabbinical family, which has a distinguished and well-established lineage, has a direct male line comprised of R1a1a Ashkenazi Levites. Because more than half of R1a1a Ashkenazi Levites may be descended from a member of the Horowitz rabbinical family who lived in the 15th century, there may not be a Y-DNA marker that is characteristic of all of the Horowitzes.
There is, however, one marker value on markers 68 through 111 – DYS495=16 – which is shared by almost all of the men who are surnamed Horowitz or who are known descendants of the Horowitz rabbinical family who have tested to 111 markers, but only by a handful of the other men who have tested to 111 markers (those other men have the R1a1a Ashkenazi Levite mode of DYS495=17). It appears that this marker value may be associated with the Horowitz rabbinical family as a whole or with one branch of that family, currently believed to be that of Shmuel Shmelke Horowitz, who lived in the 17th century. Further test results may confirm whether DYS495=16 is characteristic of all branches of the Horowitz rabbinical family; such results may also identify other marker values that are characteristic of certain branches of that family.
 The color coding is not visible in Excel 2003, which apparently does not support the conditional formatting function used in the sortable spreadsheet for color coding.
 The sortable spreadsheet excludes a few men who are identified as R1a1a Ashkenazi Levites in some Family Tree DNA projects because they do not appear to be R1a1a Ashkenazi Levites, based upon their SNPs or their distance from the R1a1a Ashkenazi Levite mode. Conversely, the sortable spreadsheet includes a few men whose results, at 37 markers, are rather distant from the R1a1a Ashkenazi Levite mode; testing SNPs or upgrading to 67 markers should confirm whether those men are in fact R1a1a Ashkenazi Levites.
 The projects are: (1) AshkenaziLeviteR1a1; (2) Horowitz; (3) Iberian Ashkenaz/EEIJH; (4) Jewish Heritage Proj; (5) Jewish Ukraine West; (6) Polish; (7) R1a & all subclades; and (8) R1a1a and Subclades.
 If a match has made his results available through a Family Tree DNA project, those results may be located by doing a Google search for the terms “Family Tree DNA” and the information provided by the match for his most distant known male ancestor, as shown on the Family Tree DNA match page.
 You can sort the column by, e.g.: (1) right clicking in the top cell of the column containing numbers; (2) clicking on “Sort,” and (3) clicking on “Sort Smallest to Largest.”
 You should start by checking your matches at the highest number of markers to which you’ve tested. Because the sample size at 111 markers is still quite small, you will probably need to compare your matches at 67 markers.
 As discussed below, there are some markers that may change by more than one step in a single mutation. Those markers are less useful in determining the order in which mutations occurred.
 The information appearing in the spreadsheet concerning mutation rates per generation is extracted from information compiled by Robert Brooks Casey at his Interactive Family Histories website, http://www.rcasey.net/, and appearing in a table saved on his website as http://www.rcasey.net/DNA/Casey/Sources/Mutation_Rates_Burgarella_2010.pdf. That table contains information concerning mutation rates from two sources. First, Family Tree DNA several years ago provided information concerning mutation rates on the first 67 markers. Second, a September 2010 article by Burgarella et al. provided mutation rates for most – but not all – of the 111 Y-DNA markers tested by Family Tree DNA based upon 29 previously published studies of Y-DNA mutation rates. The mutation rates reported in the Burgarella article differ substantially from those previously reported by Family Tree DNA, presumably because the Burgarella article was able to incorporate a much larger database of Y-DNA results. It appears that Family Tree DNA’s TiP reports may be based upon more recent reports concerning the frequency of mutations by marker, rather than the mutation frequency information provided by Family Tree DNA several years ago.
 There are some markers on which the percentage of Ashkenazi Levites with a value differing from the R1a1a Ashkenazi Levite mode is far larger than that which would be expected based upon the mutation rate for that marker. The fact that many men share a mutation on a marker that rarely mutates in the general population suggests that they inherited that mutation from a common direct male ancestor who lived long ago, since there is little likelihood of frequent, independent mutations occurring more recently.
 DYF399X is a fast-mutating three-allele marker that is of use for close genealogy. The Yahoo Groups website includes a memorandum providing the test results for the handful of men who have ordered DYF399X testing. The currently available information is insufficient to allow identification of the R1a1a Ashkenazi Levite mode for DYF399X (or a determination whether DYF399X mutates too quickly to be of use in refining matches who share a direct male ancestor 300 or 400 years ago).
 In order for such test results to provide useful information, both of the matches must have received custom test results for the same marker or markers. Accordingly, you will want to coordinate custom testing with your closest matches.
 This is especially true at 111 markers because: (1) the universe of R1a1a Ashkenazi Levite men who have tested to 111 markers is smaller; and (2) the men who have tested to 111 markers are, for the most part, more closely related to each other than are the general population of R1a1a Ashkenazi Levites.
 For example, the R1a1a Ashkenazi Levite mode for DYS464 is 12-12-15-15, but 12-15-15-16 is relatively common.
 For example, most R1a1a Ashkenazi Levite men with deviations from the R1a1a Ashkenazi Levite mode on DYS464 also appear to have deviations from the mode on CDY.
 Family Tree DNA takes this RecLOH issue into account in stating the number of steps by which matches differ and in the TiP calculations.
 Because the sample size is relatively small, it is more difficult to draw conclusions as to the significance of marker values on markers 68 through 111.
 The one man with DYS537=12 and DYS650=20 is the son of a man with DYS537=11 (and DYS650=20), demonstrating that the son’s DYS537=12 resulted from a mutation in the last generation.
 While you can conclude that deviations not shared by your match likely occurred after your line diverged from your match’s line, you cannot conclude that those deviations occurred after 1800 because your line may have diverged from your match’s line well before 1800.
 At the risk of overgeneralization: (1) some Jewish families in what are now Spain, France, Austria, Germany, and the Czech Republic had adopted surnames by the 1500s or earlier; (2) in parts of Poland and Lithuania, surnames were generally not adopted until the early 19th century; and (3) in parts of Romania, surnames were not adopted until the late 19th century. To complicate matters further: (1) Jews with surnames sometimes retained those surnames when moving to areas where Jews generally did not have surnames; and (2) it was not uncommon for Jews with surnames to change their surnames, for a variety of reasons. In short, while a common surname and a close Y-DNA match likely reflect a relatively recent shared direct male ancestor, the fact that close Y-DNA matches do not share a surname is unlikely to disprove the existence of a relatively recent shared direct male ancestor.
 Pending the receipt of more results at 67 markers and 111 markers from direct male descendants of branches of the Horowitz rabbinical family from whom we do not yet have test results, our working hypothesis is that a substantial proportion of men with DYS650=20 and DYS537=12 may be descended from the Horowitz rabbinical family, while men with DYS650<20 and DYS537=11 are likely to share an MRCA with the Horowitzes that pre-dates the 15th century (especially if those men differ significantly from the R1a1a Ashkenazi Levite mode on other markers). If we find that descendants of another Horowitz branch have DYS650<20, that would indicate that the mutation to DYS650=20 is characteristic of one branch of the Horowitz family and post-dates the move to Horovice; conversely, if we find that descendants of the other Horowitz branches have DYS650=20, that may mean that the mutation to DYS650=20 pre-dated the move to Horovice (and that not all men with DYS650=20 are descended from the Horowitz rabbinical family).
 Given the number of men who are very close matches to known Horowitzes but have DYS495=17, it appears possible that some direct male descendants of the Horowitz rabbinical family may have back mutated to DYS495=16. SNP testing may shed light on this question.
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