JGSLI DNA Project

The JGSLI DNA project is open to all JGSLI members and their families. DNA testing can be a valuable tool in finding family members on any of your ancestral lines.

By ordering your DNA tests through the Family Tree DNA JGSLI project, you receive significant savings, along with access to someone who can help interpret those results for you.

There are three kinds of DNA that genealogists commonly use to trace ancestry:

Mitochondrial DNA (mtDNA) is the DNA in the mitochondria, or energy packs in the cell. Males and females have mtDNA but only females pass it on to the next generation. Males and females can have their mtDNA tested to trace their direct maternal line- that is, their mother’s mother’s…mother’s line. mtDNA mutates slowly, and is passed along each generation relatively unchanged. The mtDNA test can tell you whether you are among the nearly 50% of Ashkenazi Jews today who are descendant from the four founding Ashkenazi mothers.

The DNA on the Y-chromosome, or Y-DNA, is useful for tracing paternal ancestry. Only males have a Y-chromosome; therefore only males can have their Y-DNA tested. Y-DNA is passed from father to son relatively unchanged each generation. A male can have his Y-DNA tested to trace his direct paternal line- that is, his father’s father’s…father’s line. Since surnames are passed along this same direct paternal line, Y-DNA is helpful in discovering whether two males with the same surname are related to each other.

Autosomal DNA is the DNA on the 22 non-sex chromosomes that gets shuffled and recombined each generation. The Family Finder test uses autosomal DNA to predict relatives on any of your ancestral lines. You inherit roughly half of your DNA from each parent, your parents inherited roughly half of their DNA from each of their parents, etc., so that about 1/2 of your DNA comes from each of your parents, 1/4 from each of your four grandparents, 1/8 from each of your 8 great-grandparents, 1/16 from each of your 16 great-great grandparents, etc. Two people who have matching segments on any of their chromosomes must have a common ancestor. We can estimate how many generations ago the common ancestor lived by measuring the length and number of shared segments. Since we don’t know exactly which ancestor contributed the matching segments, Family FInder is best used when you have reasonably good archival records so that you can compare ancestral surnames and towns with each person who shares segments on any of the chromosomes with you.

Members of the Jewish Genealogy Society of Long Island are welcome to join the JGSLI DNA project.