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Posts Tagged ‘Y chromosome’

If you want DNA genetics it is not necessary to test every member of your family.   The Y-chromosome present in the cells of all males will yield results for all male members of your family.  Women lack the Y-chromosome and have only X chromosomes.  In this case, the mitochondrion of women is tested and findings apply to the female family members.

Popular media such as the television crime dramas show conclusive proof of DNA guilt or innocence.  DNA used for genealogy is not as fool proof.   Populations have been mixing since humans first left Africa 150,000 years ago, so while a DNA marker reveals a strong link of origin to a single group, it is not 100 percent guaranteed proof since no marker has been found to lie exclusively in one group.

Researchers believe every person on earth originates from only 100,000 early individuals and in some ancient way we are all related; your neighbor, your colleague, your best friend:  Even famous and infamous individuals like President Roosevelt or Henry VIII !

In spite of the scientific advances in DNA technology, the test is relatively simple.  A painless cheek swab is sent to a lab for analysis.  Technicians extract, amplify and analyze the cellular sample and then compare and match it to DNA samples from a database of other samples.  At this point they are looking to link it to a particular haplotype which is a grouping of closely linked genes.

When a person is found to share maternal or paternal ancestry lines with other people it is called lineage testing.  There is another kind of analysis called admixture testing which centers on 22 pairs of chromosomes not related to gender such as the Y which is exclusive to men and the X present in men and in women.

Regardless of the method you choose, DNA genetics will yield far more information about your ancestors than mere historical records can show.

Genealogists turn to ancestral DNA testing to answer questions that historical records alone cannot.  All people of the world have DNA so it makes sense they would form a large information base about the evolution of humans.

It isn’t necessary to test every member of a family to learn their origins.  Women carry mtDNA because they lack the Y chromosome that men have to determine the male gender.  Brothers and sisters share the same mtDNA and brothers share the same Y DNA.   MtDNA yields information about the maternal line of a family.  Mt is short for mitochondria present in both men and women.  Y DNA tests the paternal line.

Here is what you can learn from a DNA test for ancestry:

Do your ancestors originate from Europe, or the farmers from the Middle East?  Europeans came from seven maternal clans and your DNA can spot the markers that show the specific area of Europe where your mother’s family originated.

Even if you are Caucasian you may discover a bloodline that points to Africa and the oldest human population from 100,000 years ago.  Some of the early tribes are the Bantu, Ibo and Kung.

Native Americans are predominately from four clans which migrated from the Old World.  Native Americans today seek to know which modern tribe they are from and DNA evidence of early tribal migration narrows the focus of an otherwise broad population sample.

Some families today are conducting surname projects to learn the origin of their last name.   Whether the name is Jones or Andrianopoulos, families want to know who they are related to around the world.

The human race has been mixing since it evolved in Africa 150,000 years ago.  You may find identifying markers from several groups that don’t seem connected because of the constant evolution of families.  If you’re looking for many answers to specific questions, proceed with ancestral DNA testing with an open mind.  Collectively the more people that do have genealogy DNA testing performed will help to grow the database for the overall study.

One thing that DNA testing for genealogy shows is,  if you are a male, you have the same biological component as your father, your grandfather, your great-grandfather, your great, great grandfather and your g-g-g-g-g-grandfather.

That component is called the Y-chromosome, part of the genetic ribbon of information that makes every male, male.   When you test your Y-DNA, you can determine whether you are or are not related to another male with the same surname.  You might even want to join the growing list of surname projects going on across the country.

DNA, or deoxyribonucleic acid, exists in almost all cells and is the building block for a human being.  DNA determines genetics and whether your eyes are blue and your hair is straight.  It also predicts the risk for health disorders or diseases, so there is much to be learned through DNA testing that goes beyond ancestry.

The way genealogists approach DNA testing is they look for mutations.  In other words, a mutation is a change in the DNA sequencing.  Cells in our body increase by dividing in a process called mitosis.  An enzyme called polymerase uses the original DNA helix as a template and then builds a whole new cell using the same DNA code.

Occasionally a mutation in this process occurs and gets passed on.  It is rare; approximately 0.2% per generation, but it does signal a break in the identical ancestral code that gets passed from father to son.

There are DNA genealogy tests for women, even if they do not have a Y chromosome.  For women, scientists rely on the mitochondrial DNA which gets passed from the mother to all her offspring.

It’s fascinating that with the help of a single cheek swab DNA testing for genealogy can track the history of your surname, or even your ancient ancestors as they migrated from East Africa 80 thousand years ago.