Lara's Jewnealogy: Ashkenazic Shared DNA Survey

Sunday, September 1, 2019

Ashkenazic Shared DNA Survey - September 2019 Update

An updated version of this post is here.

Thank you to everyone who has contributed data about shared DNA in people with Ashkenazic ancestry! I have 5537 data points to analyze, and that should help the entire genetic genealogy community (I'm still collecting data--you can find out more about the project and how to contribute here).

This iteration looks at how shared DNA will differ depending on how much (documented) Ashkenazi DNA each individual has.

There are four tables below:

Table 1 looks at all 5337 data points, regardless of Ashkenazic percentage
Table 2 looks at those data points where both individuals are documented to be 100% Ashkenazic
Table 3 looks at those data points where one individual is documented to be 100% Ashkenazic and the other 50% Ashkenazic
Table 4 looks at those data points where both individuals are documented to be 50% Ashkenazic
Table 5 looks at those data points where one individual is documented to be 100% Ashkenazic and the other 25% Ashkenazic
Table 6 looks at those data points where one individual is documented to be 50% Ashkenazic and the other 25% Ashkenazic

While I do have data for lower Ashkenazic percentages, at this point, I have so few data points that there isn't enough information to draw any conclusions. (You can see how few data points I have for the 50%/25% comparison below.)

Table 1: All responses (regardless of Ashkenazic percentage; 5337 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	211	3377	3730	3523.66	203.4	287	270.45
Siblings	212	2246	3037	2678.14	19.2	281.5	186.19
Half Siblings	34	1286	2167	1836.42	79.4	253.7	145.89
Grandparent/Grandchild	37	1368	2312	1843.01	92.4	263.7	180.82
Great Grandparent/Great Grandchild	7	618	1001	785.56	67	126	97.93
Great-great Grandparent/Great-great Grandchild	1	511	511	511	88	88	88
Uncle or Aunt / Niece or Nephew	246	671	2303	1786.53	35	268.8	125.46
Half Uncle or Half Aunt / Half Niece or Half Nephew	23	638.1	1317	943.54	64.8	161.5	110.07
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	44	363.3	2034.6	895.6	27	237.6	92.09
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	6	620.3	1019.5	855.52	52.1	107	74.83
First cousins	401	383	1610	927.68	18	221	83.96
First cousins once removed	556	7	1878	486.96	15	133.2	60.03
First cousins twice removed	97	0	537	252.77	0	108	44.45
First cousins three times removed	25	51.9	302.8	133.65	17	72.1	34.69
Half first cousins	19	192	852.6	531.92	24	150.7	75.79
Half first cousins once removed	42	63.7	500.1	266.98	23	114.6	53.17
Half first cousins twice removed	5	82.2	212	156.84	36	75.5	59.97
Half first cousins three times removed	2	34.7	54.8	44.75	9.2	10.4	9.8
Second cousins	877	6.8	698	273.34	6	423	47.66
Second cousins once removed	818	0	446	167.03	0	565.1	37.7
Second cousins twice removed	132	0	285.7	108.13	0	78.5	29.06
Second cousins three times removed	27	0	177	85.02	0	32	19.77
Half second cousins	93	30	313	153.15	11.8	85.5	38.09
Half second cousins once removed	108	0	243	88.96	0	63	24.33
Half second cousins twice removed	16	0	91.8	40.43	0	35.1	16.22
Half second cousins three times removed	4	30.5	47.9	39.2	12.3	22.8	17.55
Third cousins	435	0	315	114.87	0	91	27.29
Third cousins once removed	395	0	215	77.4	0	68	21.03
Third cousins twice removed	49	0	173	63.16	0	43.89	15.96
Third cousins three times removed	1	46	46	46	0	0	0
Half third cousins	70	0	101.9	30.04	0	32.1	9.37
Half third cousins once removed	21	0	79.3	17.65	0	18.8	5.07
Half third cousins twice removed	1	108	108	108	10	10	10
Fourth cousins	257	0	664	52.61	0	55.6	13.19
Fourth cousins once removed	113	0	148	37.97	0	41.5	10.44
Fourth cousins twice removed	7	0	102.4	58.57	0	31.2	10.87
Half fourth cousins	32	0	80.1	26.11	0	67.9	15.09
Half fourth cousins once removed	6	0	62.1	33.42	0	62.1	21.48
Half fourth cousins twice removed	1	109	109	109	6	6	6
Fifth cousins	31	0	116	29.7	0	22.5	4.82
Fifth cousins once removed	30	0	143.8	42.34	0	38.9	9.47
Sixth cousins	5	0	109.5	47.82	0	28	11.16
Sixth cousins once removed	7	0	113.8	74.83	0	32	18.34
Half sixth cousins	2	75	114	94.5	5	5	5

Table 2: Both testers with known 100% Ashkenazi ancestry (3799 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	153	3379	3730	3523.85	203.4	284.26	269.05
Siblings	175	2246	3037	2681.96	19.2	281.5	186.39
Half Siblings	9	1754.1	2167	1983.77	99.27	253.7	145.81
Grandparent/Grandchild	19	1426	2215.1	1825.33	114.5	237.6	177.92
Great Grandparent/Great Grandchild	1	673.9	673.9	673.9	91.5	91.5	91.5
Great-great Grandparent/Great-great Grandchild	-	-	-	-	-	-	-
Uncle or Aunt / Niece or Nephew	193	671	2303	1794.24	35	223.7	123.24
Half Uncle or Half Aunt / Half Niece or Half Nephew	4	954.418	1171	1047.0095	91.23	110.4	98.7413333333333
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	19	364	2034.6	870.28	27	237.6	91.83
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	6	620.3	1019.5	855.52	52.1	107	74.83
First cousins	299	434.1	1610	929.42	29	167	83.2
First cousins once removed	432	61.2	1878	498.42	15	133.2	60.65
First cousins twice removed	46	137.1	439.4	266.4	14	79.1	44.29
First cousins three times removed	3	92	170.1	131.05	20.7	37.8	29.25
Half first cousins	11	192	852.6	529.62	24	150.7	72.35
Half first cousins once removed	37	89.8	500.1	273.98	23	114.6	55.69
Half first cousins twice removed	3	162	212	184.67	74.3	75.5	74.9
Half first cousins three times removed	2	34.7	54.8	44.75	9.2	10.4	9.8
Second cousins	638	6.8	698	280.08	13	423	47.55
Second cousins once removed	565	0	446	172.07	0	565.1	36.8
Second cousins twice removed	69	17.6	285.7	118.35	9.9	78.5	29.64
Second cousins three times removed	18	0	177	95.52	0	30.6	19.51
Half second cousins	66	30	257	152.33	11.8	85.5	37.78
Half second cousins once removed	63	8.2	243	97.16	8.2	63	23.83
Half second cousins twice removed	10	0	91.8	40.53	0	27.3	14.39
Half second cousins three times removed	2	47.9	47.9	47.9	22.8	22.8	22.8
Third cousins	311	0	315	122.38	0	91	26.7
Third cousins once removed	259	0	205	80.37	0	68	19.55
Third cousins twice removed	35	0	173	71.78	0	40.8	16.04
Third cousins three times removed	1	46	46	46	-	-	-
Half third cousins	21	0	101.9	45.75	0	17	10.95
Half third cousins once removed	5	0	79.3	34.58	0	15	8.18
Half third cousins twice removed	1	108	108	108	10	10	10
Fourth cousins	172	0	664	60.79	0	48	14.11
Fourth cousins once removed	78	0	148	43.52	0	38.8	10.48
Fourth cousins twice removed	7	0	102.4	58.57	0	31.2	10.87
Half fourth cousins	-	-	-	-	-	-	-
Half fourth cousins once removed	-	-	-	-	-	-	-
Half fourth cousins twice removed	1	109	109	109	6	6	6
Fifth cousins	28	0	116	25.81	0	14.8	4.01
Fifth cousins once removed	27	0	143.8	44.48	0	38.9	9.44
Sixth cousins	4	0	109.5	43.58	0	28	10.48
Sixth cousins once removed	4	0	113.8	78.45	0	27.8	14.6
Half sixth cousins	2	75	114	94.5	5	5	5

Table 3: One tester with known 100% Ashkenazi ancestry and one with known 50% Ashkenazi ancestry (821 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	21	3377	3587.1	3503.36	263.7	284.3	273.58
Siblings	-	-	-	-	-	-	-
Half Siblings	17	1286	1960.4	1756.16	79.4	198.9	151.17
Grandparent/Grandchild	9	1368	2143.2	1792.42	147.36	263.7	192.95
Great Grandparent/Great Grandchild	-	-	-	-	-	-	-
Great-great Grandparent/Great-great Grandchild	-	-	-	-	-	-	-
Uncle or Aunt / Niece or Nephew	22	837.1	2155	1682.32	59	268.8	136.22
Half Uncle or Half Aunt / Half Niece or Half Nephew	13	771.7	1157.5	933.17	84.5	161.5	111.93
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	10	363.3	1141	835.92	49.2	114	89.96
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	-	-	-	-	-	-	-
First cousins	45	383	1345	949.88	52	145.7	82.94
First cousins once removed	76	7	844	432.25	29.5	109.55	58.69
First cousins twice removed	17	128.7	451.9	254.73	30	108	49.77
First cousins three times removed	2	96	105	100.5	17	17	17
Half first cousins	1	558	558	558	119	119	119
Half first cousins once removed	-	-	-	-	-	-	-
Half first cousins twice removed	1	148	148	148	36	36	36
Half first cousins three times removed	-	-	-	-	-	-	-
Second cousins	105	69.7	658.1	264.86	15	137.7	53.28
Second cousins once removed	108	21.5	433.4	155.49	12.8	122	40.37
Second cousins twice removed	28	30	248.7	97.59	8	55.1	29.57
Second cousins three times removed	1	95.5	95.5	95.5	5	5	5
Half second cousins	15	105	313	178.69	28.88	69	48.1
Half second cousins once removed	30	0	164	83.86	0	60.5	27.09
Half second cousins twice removed	6	8.3	78.3	40.2	8.3	35.1	20.33
Half second cousins three times removed	2	30.5	30.5	30.5	12.3	12.3	12.3
Third cousins	56	0	310	98.53	0	76	27.52
Third cousins once removed	60	0	215	72.25	0	67.4	23.61
Third cousins twice removed	9	0	103	40.1	0	28.03	11.9
Third cousins three times removed	-	-	-	-	-	-	-
Half third cousins	32	0	75.2	27.99	0	26	9.81
Half third cousins once removed	11	0	65.1	14.82	0	18.8	4.88
Half third cousins twice removed	-	-	-	-	-	-	-
Fourth cousins	51	0	131	31.28	0	43	9.48
Fourth cousins once removed	31	0	113.1	24.4	0	41.5	9.85
Fourth cousins twice removed	-	-	-	-	-	-	-
Half fourth cousins	30	0	80.1	24.3566666666667	0	67.9	14.22
Half fourth cousins once removed	6	0	62.1	33.4166666666667	0	62.1	21.4833333333333
Half fourth cousins twice removed	-	-	-	-	-	-	-
Fifth cousins	1	50	50	50	9	9	9
Fifth cousins once removed	2	15.7	40	27.85	10	10	10
Sixth cousins	-	-	-	-	-	-	-
Sixth cousins once removed	3	58	87	70	12	32	23.33
Half sixth cousins	-	-	-	-	-	-	-

Table 4: Both testers with known 50% Ashkenazi ancestry (61 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	3	3445	3480	3464	-	-	-
Siblings	10	2260	2938.1	2631.53	141.2	220.7	186.85
Half Siblings	3	1650.9	1826	1722.8	124.2	184.5	154.8
Grandparent/Grandchild	-	-	-	-	-	-	-
Great Grandparent/Great Grandchild	-	-	-	-	-	-	-
Great-great Grandparent/Great-great Grandchild	-	-	-	-	-	-	-
Uncle or Aunt / Niece or Nephew	3	1674	1882	1744.67	126	126	126
Half Uncle or Half Aunt / Half Niece or Half Nephew	-	-	-	-	-	-	-
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	-	-	-	-	-	-	-
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	-	-	-	-	-	-	-
First cousins	6	775.9	1069	907.98	57.1	122	99.6
First cousins once removed	2	508.7	539.9	524.3	46.1	77.9	62
First cousins twice removed	-	-	-	-	-	-	-
First cousins three times removed	-	-	-	-	-	-	-
Half first cousins	-	-	-	-	-	-	-
Half first cousins once removed	-	-	-	-	-	-	-
Half first cousins twice removed	-	-	-	-	-	-	-
Half first cousins three times removed	-	-	-	-	-	-	-
Second cousins	7	199	455.3	309.58	43.3	97	65.74
Second cousins once removed	7	44	197.2	137.07	23.6	89.2	55.08
Second cousins twice removed	1	56.1	56.1	56.1	29.4	29.4	29.4
Second cousins three times removed	-	-	-	-	-	-	-
Half second cousins	-	-	-	-	-	-	-
Half second cousins once removed	1	68	68	68	39	39	39
Half second cousins twice removed	-	-	-	-	-	-	-
Half second cousins three times removed	-	-	-	-	-	-	-
Third cousins	1	232	232	232	0	0	0
Third cousins once removed	3	104	113	108.67	26	50	34.33
Third cousins twice removed	1	46.9	46.9	46.9	9.5	9.5	9.5
Third cousins three times removed	-	-	-	-	-	-	-
Half third cousins	1	57	57	57	12	12	12
Half third cousins once removed	-	-	-	-	-	-	-
Half third cousins twice removed	-	-	-	-	-	-	-
Fourth cousins	12	0	115.9	32.93	0	35.9	10.99
Fourth cousins once removed	-	-	-	-	-	-	-
Fourth cousins twice removed	-	-	-	-	-	-	-
Half fourth cousins	-	-	-	-	-	-	-
Half fourth cousins once removed	-	-	-	-	-	-	-
Half fourth cousins twice removed	-	-	-	-	-	-	-
Fifth cousins	-	-	-	-	-	-	-
Fifth cousins once removed	-	-	-	-	-	-	-
Sixth cousins	-	-	-	-	-	-	-
Sixth cousins once removed	-	-	-	-	-	-	-
Half sixth cousins	-	-	-	-	-	-	-

Table 5: One tester with known 100% Ashkenazi ancestry and one with known 25% Ashkenazi ancestry (179 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	-	-	-	-	-	-	-
Siblings	-	-	-	-	-	-	-
Half Siblings	-	-	-	-	-	-	-
Grandparent/Grandchild	1	1891	1891	1891	0	0	0
Great Grandparent/Great Grandchild	-	-	-	-	-	-	-
Great-great Grandparent/Great-great Grandchild	-	-	-	-	-	-	-
Uncle or Aunt / Niece or Nephew	-	-	-	-	-	-	-
Half Uncle or Half Aunt / Half Niece or Half Nephew	-	-	-	-	-	-	-
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	2	728	918	823	69	76	72.5
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	-	-	-	-	-	-	-
First cousins	-	-	-	-	-	-	-
First cousins once removed	7	388	640	507.33	43	96.267	68.4
First cousins twice removed	2	171.326	250.807	211.0665	27.887	42.045	34.966
First cousins three times removed	2	81	148	114.5	20	52	36
Half first cousins	6	465	647	541.6	65	85.3	72.8333333333333
Half first cousins once removed	4	63.7	334.2	208.45	25.6	50.8	35.525
Half first cousins twice removed	1	82.2	82.2	82.2	54.1	54.1	54.1
Half first cousins three times removed	-	-	-	-	-	-	-
Second cousins	16	79.6	497	249.91	20.2	90	47.2
Second cousins once removed	53	0	409.5	177.21	0	119.19	41.03
Second cousins twice removed	4	10	175	110.5	10	51	23.75
Second cousins three times removed	1	16	16	16	0	0	0
Half second cousins	11	77	157.2	124.481818181818	17	55	32.0727272727273
Half second cousins once removed	9	0	109.6	44.18	0	33.8	16.02
Half second cousins twice removed	-	-	-	-	-	-	-
Half second cousins three times removed	-	-	-	-	-	-	-
Third cousins	14	18.3	298.5	102.81	18	81.1	38.15
Third cousins once removed	11	0	153.1	67.88	0	59.8	24.25
Third cousins twice removed	1	19	19	19	0	0	0
Third cousins three times removed	-	-	-	-	-	-	-
Half third cousins	16	0	50.8	11.83	0	32.1	6.25
Half third cousins once removed	5	0	34.8	6.96	0	11.8	2.36
Half third cousins twice removed	-	-	-	-	-	-	-
Fourth cousins	7	0	86.3	28.79	0	28.8	10.92
Fourth cousins once removed	2	0	0	0	0	0	0
Fourth cousins twice removed	-	-	-	-	-	-	-
Half fourth cousins	1	75.9	75.9	75.9	41.1	41.1	41.1
Half fourth cousins once removed	-	-	-	-	-	-	-
Half fourth cousins twice removed	-	-	-	-	-	-	-
Fifth cousins	1	47	47	47	22.5	22.5	22.5
Fifth cousins once removed	1	15.7	15.7	15.7	-	-	-
Sixth cousins	1	64.8	64.8	64.8	13.9	13.9	13.9
Sixth cousins once removed	-	-	-	-	-	-	-
Half sixth cousins	-	-	-	-	-	-	-

Table 6: One tester with known 50% Ashkenazi ancestry and one with known 25% Ashkenazi ancestry (41 data points)

Relationship	Number of submissions	Min total shared cM	Max total shared cM	Average total shared cM	Min largest segment	Max largest segment	Average largest segment
Parent/Child	4	3461	3586	3553.85	281	281.5	281.166666666667
Siblings	-	-	-	-	-	-	-
Half Siblings	-	-	-	-	-	-	-
Grandparent/Grandchild	-	-	-	-	-	-	-
Great Grandparent/Great Grandchild	-	-	-	-	-	-	-
Great-great Grandparent/Great-great Grandchild	-	-	-	-	-	-	-
Uncle or Aunt / Niece or Nephew	5	1438	1789.3	1682.62	106	160.87	132.15
Half Uncle or Half Aunt / Half Niece or Half Nephew	4	704	1101	856.775	107.3	155.7	128.866666666667
Great-Aunt or Great-Uncle / Great-Niece or Great-Nephew	-	-	-	-	-	-	-
Great-Great-Aunt or Great-Great-Uncle / Great-Great-Niece or Great-Great-Nephew	-	-	-	-	-	-	-
First cousins	1	1000	1000	1000	-	-	-
First cousins once removed	8	309.7	682	467.69	36	83.8	60.53
First cousins twice removed	-	-	-	-	-	-	-
First cousins three times removed	-	-	-	-	-	-	-
Half first cousins	-	-	-	-	-	-	-
Half first cousins once removed	-	-	-	-	-	-	-
Half first cousins twice removed	-	-	-	-	-	-	-
Half first cousins three times removed	-	-	-	-	-	-	-
Second cousins	6	248	483	314.67	40	113	70.33
Second cousins once removed	3	96	192	151.67	12	35	25.33
Second cousins twice removed	1	53	53	53	27.3	27.3	27.3
Second cousins three times removed	-	-	-	-	-	-	-
Half second cousins	-	-	-	-	-	-	-
Half second cousins once removed	-	-	-	-	-	-	-
Half second cousins twice removed	-	-	-	-	-	-	-
Half second cousins three times removed	-	-	-	-	-	-	-
Third cousins	4	37.2	291	110.025	12.7	23	17.85
Third cousins once removed	1	52.8	52.8	52.8	28.2	28.2	28.2
Third cousins twice removed	-	-	-	-	-	-	-
Third cousins three times removed	-	-	-	-	-	-	-
Half third cousins	-	-	-	-	-	-	-
Half third cousins once removed	-	-	-	-	-	-	-
Half third cousins twice removed	-	-	-	-	-	-	-
Fourth cousins	4	15.8	47.7	24.88	13.6	16.3	15.33
Fourth cousins once removed	-	-	-	-	-	-	-
Fourth cousins twice removed	-	-	-	-	-	-	-
Half fourth cousins	-	-	-	-	-	-	-
Half fourth cousins once removed	-	-	-	-	-	-	-
Half fourth cousins twice removed	-	-	-	-	-	-	-
Fifth cousins	-	-	-	-	-	-	-
Fifth cousins once removed	-	-	-	-	-	-	-
Sixth cousins	-	-	-	-	-	-	-
Sixth cousins once removed	-	-	-	-	-	-	-
Half sixth cousins	-	-	-	-	-	-	-

Note that some relationships don't have enough data to really do anything statistically. But as more people enter data, perhaps they will reach that threshold. Please contribute more data if you haven't already!

And while I have data for people who have other known Ashkenazic ancestral percentages, there really isn't enough data from which anyone can draw conclusions, which is why I stopped where I did.

Remember, you can still contribute information about your own family's shared DNA to the project. Information on this project and how to participate is here. Particular if you (or a known relative) has partial Ashkenazic ancestry, please contribute your data so that future posts can include additional Ashkenazic percentages.

You can now like my page on Facebook:

or follow @larasgenealogy .

21 comments:

Bonnie MullerSeptember 1, 2019 at 8:08 PM
My brother(I am adopted) & our 1st cousin test between 23-26% Ashkenazi. The one cousin, a second cousin, who has tested from our grandfathers family is 100% and has 165 cM across 9 segments. This falls in the range you show on table 5. The only other match I can identify is a half 2nd cousin 1xR. She is 50% and shares a whopping 15.2 cM. I would not have found her because I do not spend time on matches this low, but she has an unusual family name I did a search for.
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Ben KempnerSeptember 2, 2019 at 1:58 PM
Lara, thank you for leading this research. It will be very helpful to anyone with Ashkenazi roots, especially when you get even more data points. I was a little surprised to see just small differences between the AJ data and what's on the DNA Painter shared cM site. Do you have any initial summary analysis on the differences between AJ data and DNA Painter data - especially for the "both testers 100%" scenario?
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JBSeptember 5, 2019 at 10:17 PM
Hi Lara . Ive completed compilation of most of my personal family DNA test results and will submit 109 different forms tomorrow. These are from Parent out to 5C1R who go as low as 91% and a number of 50/50's. I have a few 4C cousins who still live in Russia and the father has 89% and the daughter 36%. Another Russian father/daughter pair have 43-45 as the mother was also approx 50%. What do you consider the 89% and 36% pair. 75 25 or 100 50??

I have other data from my 25% to 50% Ashkenazi work but would have to get permission from each of the families even though they cannot be identified.
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GraceDecember 8, 2019 at 8:42 PM
Hello,

I am dealing with endogamy, but I am black. Ancestors on my mother's side are from an area in South Carolina where there was apparently a lot of intermarriage. Can I use this chart to estimate relationships? My mother was a foster child and I am trying to figure out who her birth parents were. I'm not sure how to figure out the exact relationships with her DNA matches. For example, she has one with 435 cM and 24 segments on Ancestry. Is she as close a relation as the numbers suggest?
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AmyJanuary 21, 2020 at 11:21 AM
Hi Lara, I went back to this post because my mother has a match on FTDNA who shares 79 cM but no segment larger than 5 cM. There is a possibility that they are third cousins once removed or perhaps more distant based on a shared surname, but I am wondering how to interpret the amount of DNA shared when the segments are all so small. Any ideas?
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AnonymousMay 20, 2020 at 10:28 PM
These tables are invaluable. However, something seems amiss with 664 cM maximum for fourth cousins (100% AJ both sides). That's almost as much as the max for second cousins and much more than for third. (I'm including some fourth cousins to each other on a chart that I'm compiling to perhaps shed light on whether two branches on my tree descend from a couple or only a GGgF. The fourth cousins are too far out to have meaningful matches, but I want to include them to encourage their interest.)
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Paul K. HattoriJanuary 17, 2021 at 5:49 AM
Thanks for all your effort. On tables 1-3 might it please be possible to look again at the info for the maximum longest segment for the 2C1R set?
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Yaakov LennApril 24, 2021 at 4:15 PM
Shalom Lara:

How do you take endogamy into account when researching you Ashkenazic family roots. Do your tables take this into account?

Thank you.

Yaakov Lenn
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CrobinJune 27, 2021 at 12:15 PM
Thanks for your efforts! I have when researching who AJ ancestry but on one or two branches. The shared cM project table tends to align well. The more endogamy across multiple branches the less so. Often testers are dissuaded to follow a clue thinking it may be too distant, which is what they hear in FB DNA groups, while some have found it can still line up per the chart if they have one or two AJ branches.
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Manny YoungJune 9, 2022 at 6:04 AM
Hi, Lara! Thank you so much for organizing this project, and especially accounting for those like me who are of about 50% AJ ancestry as well as those with other percentages. This was precisely the kind of info I'd been hoping to find with regards to how much our predicted relationships are potentially overestimated by standard algorithms

I do have 3 questions, 2 pertaining to the site and 1 much more general:

1. The other day, I submitted 4 responses before realizing that they are ineligible for the purposes of the study due to my misunderstanding some of the guidelines for submission. (That was totally my bad, and I apologize for that.) Would you be able to locate a set of 4 responses from the same Gmail account that were submitted around 06/05/2022, 1 of which involving a 1C1R with 50% AJ ancestry and a longest shared segment of 52 cM? If so, please disregard those responses, and if not, please let me know what further info I can provide without listing my email address. Either way, I greatly apologize for the inconvenience caused.

2. Since the form hasn't been deactivated, I'm assuming that you're still collecting responses as of now. If that's the case, will there be another update in the not-so-distant future with current aggregate data? (No rush, of course, since I know you're likely very busy.)

3. Now for the general question: When a person like me with 50% AJ ancestry is evaluating a DNA match with any amount of AJ ancestry, what thresholds would you recommend for determining whether a match is genuine, and how should I go about reducing the total shared cM for the purposes of "manually" adjusting the relationship distance (even if the site claims that they already do this)?

Apparently, 23andMe only makes the adjustments for people with 95+% AJ ancestry per their FAQ, and I read that Ancestry only makes the adjustments for predicted relationships of estimated 4th cousins and further. Case in point: I have a set of matches on Ancestry related closely to each other, all with full AJ ancestry, and the eldest two of them (full siblings) share about 175 cM and 200 cM with me respectively, both with longest shared segments of around 40 cM. This suggests a relatively close 2nd or 3rd cousin tier relationship with them were it not for our shared AJ ancestry. However, if Ancestry is counting all of their shared cM instead of dumping the potentially trivial segments like they do with the more distant matches (i.e. the difference between "shared DNA" and "unweighted shared DNA"), then I can't really consider the predicted relationships with these "2nd-3rd cousin" matches to be reliable, can I?

Assuming that I'm unable to directly contact these matches to get more info from them, what would you suggest in terms of making the corrections on my own to get a better sense of what my true relationship to them likely could be? And if they've only tested on Ancestry (which for reasons I can't fathom apparently refuses to implement even the most basic of DNA match comparison tools for its users), by about how much should I "manually" reduce the total shared cM in order to get a relatively more accurate relationship prediction if it's above the point where they automatically make the adjustments?

Again, I understand you're very busy, so if you're not up for addressing the latter 2 questions, I completely understand. However, if you are able and willing to provide any insight on the last one, even if it's just a little bit, I would be eternally grateful. Either way, thank you so much once again, especially for all your hard work on this project!
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AnonymousJuly 21, 2022 at 6:26 PM
Thank so much. Great work. Very helpful. Just one possible mistake detected, in Table 2, 100% Jewish both, SC1R longest is 565.1 which is even larger than the maximum recorded total. Much too large! Yohanan Loeffler
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Sunday, September 1, 2019

Ashkenazic Shared DNA Survey - September 2019 Update

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