Here is a double-stranded DNA molecule:
Let's start with one set of grandparents-- male surname is Blah, female maiden name Zeep
Blah yDNA will only match other direct male Blah's and Zeep mtDNA will only match female children and their female children.
In human genetics, Y-chromosomal Adam (Y-mrca) is the patrilineal human most recent common ancestor (mrca) from whom all Y chromosomes in living men are descended. Y-chromosomal Adam is thus the male counterpart of Mitochondrial Eve (the mt-mrca), the matrilineal human most recent common ancestor, from whom all mitochondrial DNA in living humans is descended. Y-chromosomal Adam is named after the Adam of the Genesis account of creation as a metaphor only. The name may seem to imply that Y-chromosomal Adam was the only living male of his time; he was not. "Y-Adam" is not even a single fixed individual but a title that continually passes on to more recent individuals as time goes on.
(your grandfather) Timmy Blah, his sons Bobby, and David Blah have Blah yDNA. His daughters Martina and Selma Blah would NOT have Blah yDNA.
(your grandfathers brother) Alvin Blah, his sons--Alvin, Dick, Wayne, Tom, Harry, Charlie, and Jerry would have Blah yDNA. His daughters Edna and Elinor Blah would NOT have Blah yDNA.
(your grandfathers son, you dad) David Blah, his son David Jr., Zeek and Clifford Blah have Blah yDNA. His daughter (your sister) Daisy Blah would NOT have Blah yDNA.
(your grandfathers son, your uncle) Bobby Blah I, his son Charlie and Bobby Blah II have Blah yDNA.
(your uncles son) Charlie Blah and his son Charlie Blah Jr. have Blah yDNA
(you) Clifford Blah have Blah yDNA
(your brother) Zeek Blah, has Blah yDNA
(your brother) David Blah Jr., has Blah yDNA
(your son) Wayne Blah, has Blah yDNA and his son Leo Blah has Blah yDNA.
(your grandson) Leo Blah, has Blah yDNA
So as you can see you follow the male Blah surname and they will all have Blah yDNA
If you follow the Blah line back (great grandfather, gg grandfather, etc.) you might be able to find connections to the Blah line farther back, since male Blah cousins will have the same DNA and may do DNA testing and your results match them and you can compare family histories expanding your search.
Here is yDNA Haplogroups:
Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is defined as the matrilineal most recent common ancestor (MRCA) for all living humans. Allan Wilson's naming Mitochondrial Eve after Eve of the Genesis creation story may be considered unfortunate in that it has led to some misunderstandings among the general public. A common misconception is that Mitochondrial Eve was the only living human female of her time — she was not. Had she been the only living female of her time, humanity would most likely have become extinct due to an extreme population bottleneck.
Indeed not only were many women alive at the same time as Mitochondrial Eve but many of them have descendants alive today. They may have left descendants via either son or daughters (and grandsons or granddaughters, and so on). Nuclear genes from these contemporary women of Mitochondrial Eve may be present in today's population, but mitochondrial DNA from them is not.
Josephine Zeep mtDNA would be found in all her children, Martina, Charles, Anthony, Selma, Sally, Joseph, Laura and Daniel Blah BUT only would be passed down the female line.
Martina (Josephine's daughter) would pass the Zeep mtDNA to Walter, Vince, Charles, Jerome, Elizabeth and Nellie.
Nellie is the only daughter of Martina that had children and the Zeep mtDNA would be passed on to her female children June and Joyce (and they would pass it down to their female off spring, etc.). Her male children Tom, Dick and Harry would have her mtDNA but they would NOT pass it on to their children.
None of the Zeep mtDNA would be passed down the male lines.
Selma (Josephine's daughter and Martina's sister) would be passing the Zeep mtDNA on to her female child Daisy (Josephine's granddaughter), and Daisy would pass it on to her children Beverly, Brenda and Joanne (and they would pass it down to their female off spring etc.)
Beverly (Josephine's great granddaughter) would be passing down the Zeep mtDNA on to her female children Mary Beth and Rose. Mary Beth and Rose (Josephine's gg granddaughter's) would pass it on to Helen and Kathy (Mary Beth's daughters, Josephine's ggg granddaughter) and Esther and Annie (Rose's daughters, Josephine's ggg granddaughter) and they would pass the Zeep mtDNA down their female off spring etc.
If you follow the Zeep line back (great grandmother, gg grandmother, etc.) you will find that the maiden name switches and so tracking mtDNA can be a bit more difficult. You might be able to find connections to the Zeep line father back, since Zeep female cousins will have the same mtDNA and may do mtDNA testing and your results will match them and then you can compare family histories expanding your search. What you have to remember is the maiden surname will most likely not be Zeep when you find the mtDNA match.
Here is mtDNA Haplogroups:
Now some folks get confused with DNA testing and who they are related too DNA wise (which is different than being related genealogically). Lets look at a grandmother that was a Blah (maiden name) and a grandchild wants to be tested so they can find a Blah yDNA connection, testing yourself won't give you a Blah yDNA connection. Males need to realize the mtDNA stops with them and does not get passed along through them.
Example-Your gg grandfather was a Blah and his wife (your gg grandmother) was a Zeep.
Your great grandfather was a Blah, he married Susan Badlad, they have a daughter who is your grandmother Sadie (maiden name Blah) Duegood (she married Tim Duegood). You would have no Blah yDNA (since fathers can't pass yDNA to daughters) and she would have her mothers mtDNA (Badlad mtDNA, since mothers pass their mtDNA to their daughters, on down the female line) not Zeep mtDNA, so her children (your father) and his children (you), etc. would not have Blah yDNA or Zeep mtDNA.
Put together by Jill 2011