Triangulation simply explained

Two genealogists meet accidentally and after exchanging rituals of politeness one of them says she had just discovered that she had a Daughter of the King as founder of her matriline in Canada.

–Curious! me too! Which one?
–Marguerite MATRET.
–OMG! What a coincidence! Me too!

–You do not know what? It seems that if it is true then we should both have the same mitochondrial DNA signature. Moreover, our signature would be that of Marguerite MATRET transmitted from mother to mother down to us.

« You mean by the uterine lineage of the mothers? »
–Yes. You know what? Each of us will have her DNA tested independently and we will then compare our results.

–Okay.

One month later the results of this two genealogists fall into their respective personal family tree page and they find that their respective mt-DNAs belong to the haplogroup H1n5 and that they possess exactly the same mutations rCRS: T146C T195C A263G 315.1C T471C T16519C.

Each of them drew up her list of mothers as far as Marguerite MATRET and they compare them to find that their matrilineages arrive on Marguerite MATRET by two of her different daughters.

The first one arrives on the matriarch by Françoise MICHAUD MICHEL who married Gilles DUPONT in 1670 (GFAN # 1435)
And the second by Marie Louise MICHAUD MICHEL who married Jean DAGNEAU dit LAPRISE on September 10, 1670 in Quebec City (GFAN # 1395)

–You know what? We have just triangulated the signature of our matriarch Marguerite MATRET
– Oh yes, how’s that?

Follow my reasoning well.
If we both descend from Marguerite MATRET according to our matrilignages and we both have the same DNA-mt signature,
Given the law of mt-DNA transmission which is that mitochondrial DNA is transmitted from mother to daughter along the uterine lineage,

Then we must conclude that our signature is indeed that of Marguerite MATRET

« You’ll tell me so much! » One does not have to dig up her old bones to know her mitochondrial DNA since it is ours!

« We have just demonstrated, almost as a proof, that our documentary research in mothers’lines is valid, is conform with reality. We are both descending from Marguerite MATRET!

–Great!

This triangulation can be found at http://miroise.org/catalogue/tri0073/
And if the two genealogists had known the existence of the Catalogue of ancestral signatures [http://triangulations.ca] they could have predicted their mtDNA values, knowing in advance that it would belong to haplogroup H1n5 with the following rCRS mutations : T146C T195C A263G 315.1C T471C T16519C.