Bunch of How DNA Hapologrouping Works Questions

[USMC7312]

1. When determining Hapologroup membership, does matching always start DYS 393?
2. If DYS 393 is equal to 14, is there a methodology or site that tells you what Hapologroups have 14 for their value.
3. If you look at the values of the STR for the Hapologroups U106 and are find for example DYS 390 equals 23 to be a member but your value is 24 is it safe to go back up one node L11 or sideways one node P312 to find the right group where DYS 393 equals 24?
4. I understand that mutations occur but is this documented on a site for the acceptable mutations for U106 on a particular STR.

[dna]

1. When determining Hapologroup membership, does matching always start DYS 393?
2. If DYS 393 is equal to 14, is there a methodology or site that tells you what Hapologroups have 14 for their value.
3. If you look at the values of the STR for the Hapologroups U106 and are find for example DYS 390 equals 23 to be a member but your value is 24 is it safe to go back up one node L11 or sideways one node P312 to find the right group where DYS 393 equals 24?
4. I understand that mutations occur but is this documented on a site for the acceptable mutations for U106 on a particular STR.

In my opinion, you cannot do that unless you have some additional SNP information beforehand, and if you had that information you would not be guesstimating a haplogroup (based on SNPs) from STRs.

Just buy the SNP pack (or Big Y).

Mr W

P.S.
STRs only correlate with SNPs, do you want to be in that small percentage that is off?

[MMaddi]

If the OP is interested specifically in predicting U106 status, about 95% of U106+ men have DYS492=13. That's opposed to about 95% of U106- men who have DYS492=12.

Those are very good odds for predicting U106 status without a SNP test, but 5% of men who predict based on the DYS492 value will be wrong. That's why SNP tests exist, because they give you a result that's certain, not just a prediction.

However, DYS492 is the 66th marker, so only those with 67 markers tested will be able to use that information. The other thing is that DYS492 is the only single STR I know of that is so predictive of SNP status. In general, you want to have a signature of at least 3 STRs that correlate strongly with a certain SNP. A single STR (except for DYS492) is not a reliable predictor for SNP status.

[USMC7312]

When you say U106-, are you just saying that those DYS492 =12 are not part of U106?

As a follow up, is there a place that will define the requirements for a specific Hapolotype? For Example, U106 requires DYS492=13

[dna]

When you say U106-, are you just saying that those DYS492 =12 are not part of U106?

As a follow up, is there a place that will define the requirements for a specific Hapolotype? For Example, U106 requires DYS492=13

DYS492 is a short tandem repeat (STR). Haplogroups are defined by single nucleotide polymorphisms (SNPs).

There is not a one-to-one correspondence between STRs (or more precisely haplotypes) and SNPs. As MMaddi has explained there are only certain probabilities.

Haplotypes, c.f. http://www.familytreedna.com/learn/faq-items/haplotype/, are not haplogroups.

Mr W

[MMaddi]

When you say U106-, are you just saying that those DYS492 =12 are not part of U106?

As a follow up, is there a place that will define the requirements for a specific Hapolotype? For Example, U106 requires DYS492=13

dna's response immediately above mine is entirely correct. There is a strong correlation (NOT causation) between R-M269 men having DYS492=13 and being U106+. That means one does not cause or require the other, but they are seen together at a high rate.

So, your statement that I've bolded above is not true. What about the roughly 5% of U106+ men who don't have DYS492=13? They disprove your statement.

If you want to know your most downstream SNP, don't try guessing or predicting based on this or that STR. If you have DYS492=12, my suggestion is to order the R1b-M343 Backbone SNP pack. If you have DYS492=13, order the R1b-U106 SNP pack, as long as you're comfortable with there being a 5% chance that you've ordered the wrong SNP pack.

[USMC7312]

I have ordered the R1b-M343 Backbone SNP pack pack and expect results anyday