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Source
- FTDNA R1b Haplogroup Project
Related
- R1b Marker distribution of values, non-aligned
- R1b Modal Marker Values for 4060 Kits extracted November 2912
- YDNA R1b Haplogroup Marker Modes
- YDNA Marker Mutation Rate vs Modes
The data
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The following is based on data extracted from the FTDNA R1b Haplogroup Project. A total of 4060 kits are represented in these data. The data exclude an additional 365 records in the FTDNA database which listed the kit as as belonging to a different haplogroup, or for which processing was incomplete at the time of data extraction. Many of the latter kits represent imports from other projects which do not look at all of the markers included in the FTDNA testing regime.
Some marker test results include multiple variants (e.g, DYS464 which includes results for variants a, b, c and d.) Occassionally additional variants (e.g, DYS 464 e, f, g...are also recored. Such occurrences are rare occurrences, and when encoutered were deleted from the data.
Finally, while over 4000 kits were included in this sampling, not all kits sampled the full suite of markers. FTDNA kits routinely report 12, 25, 37, 67 or 111 markers (including the ones with variants such as DYS 464a, b, c....), depending on the choice of its clients. [1] This means that the results for some markers are based on more kits than were available for other markers. This is an unavoidable limitation that limits the accuracy of the results. To accomodate for this to some extent, the data have been normalized as percentages. Thus, while the results for some marker may be based on 4060 kits (those tested for 12 markers), and others on as few as 517 kits (those tested for 111 markers) the results, expressed as percentages of the kits actually tested for each marker, are still directly comparable. It should be kept in mind that results based on 4060 kits are much more reliable than those based on 517 kits. However, if we restrict the examination to only the markers most sampled we exclude most of the markers for which data is available.
The data have been displayed as graphs of each individual marker, aligned along the modal peak, and displayed using the 3-D function of Excell.
- Figure 1 (top left) shows the 3-D view of the distribution of values for each of 111 markers in the FTDNA R1b Project. Note that the distribution for each marker is aligned with the modes of the other markers. In addition, the markers have been reordered so that the markers with the smallest modes are in front, and the largest are in the rear. See R1b Marker distribution of values, non-aligned for a view of the same data not aligned, with the order of the markers in the normal FTDNA sequence.
- Figure 2 (top right) shows the same data, but in a 2-D worms eye view
- Figure 3 (bottom) ahows the data viewed from the side.
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Discussion
| Haplogroup R1b is believed to have originated from a single individual living in western Asia (e.g., Anatolia/the Levant). [2] Its parent haplogroup (R1) is thought to have arisen by 20K YBP, so R1b would be somewhat younger than that, but a definitive date has not been determined. In recent years the date of origin of this group has risen from about 4K YBP in 2004, to about 18K YBP in some recent (2012) estimates.
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Irrespective of when he lived, the YDNA signature for the patriarch for this group is presumed to have corresponded to the modal values found in his modern day descendants. Initially, all descendants of this patriarch shared the same values for each of the 111 markers examined in the FTDNA database. Overtime, mutations have occurred driving descendants marker values away from the modal value, such that a gaussian-shaped distribution results. In this view mutations occurred randomlyeither adding or removing .....
| Figure 4. Distribution of R1b kits with various marker values about the modal value for DYS455 and CDYa. These markers show the extreme range of variability found in the data.
For some markers, the modal value for the distribution is relatively unchanged from the ancestral mode. Ninety eight percent of the kits tested for DYS455, for example, retain the original patriarchal modal value of 11. Other markers, such as CDYa, show less than 30% of the kits retaining the patriarchal mode (36 in the case of CDYa). In general,
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These differences are attributed to differences in mutation rates for the various markers. Source:Chandler, 2006 has published widely accepted mutation rate estimates for many of the markers used by FTDNA in their YDNA.
Footnotes
- ↑ Different clients choose different levels of testing depending on their individual needs. Some only require a 12 marker test, while others need the full 111 marker test.
- ↑ See Wikipedia:Haplogroup R1b (Y-DNA).
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