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DNA as a Tool in Your Family Research Toolkit
Genetic Genealogy DNA as a Tool in Your Family Research Toolkit Welcome Introduction Activity-Say your name and whether or not you have any experience with traditional genealogy and if you have done a DNA test done or not. KEEP IT SHORT DNA is only a tool-without a set of traditional genealogy papers you might not just waste your money, but come to very wrong conclusions If you have not done some research at least 3-4 generations back you will not likely get much help from doing your DNA. If you are adopted DNA is the modern “Hail Mary” pass, which might or might not give you any clues at all
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What Is Genetic Genealogy?
The Types of DNA Tests The Companies that Test How Results are Determined The Take-Away In the next 40 minutes or so we will cover: Types of DNA Tests The Companies that do the tests and how they differ How Results are determined What to take away from this
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What is DNA? But before we can get into that you first need a very simplified explanation of a very complicated thing. DNA is Deoxyribonucleic acid (DNA) A chemical consisting of a sequence of hundreds of millions of nucleotides found in the nuclei of cells containing the genetic information about an individual. It is shaped like a double-stranded helix, which consists of two paired DNA molecules and resembles a ladder that has been twisted. The "rungs" of the ladder are made of base pairs, or nucleotides with complementary hydrogen bonding patterns. Source: The human genome is 99% shared amongst all humans. It is in the 1% of DNA where our differences lie
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The Cell The Human Cell is a marvelous thing. It has all the genetic code to know what to do, when to do it and goes about its business with little interference from us. The typical cell is replicating constantly. It basically splits itself in half-creating a clone of itself. Certain cells do things a little differently when the time comes for human reproduction and that is what makes it possible to tie genetics and genealogy together.
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Chromosomes are clustered the Nucleus
Mitochondria swim around the Nucleus and carry the Mitichondrial DNA Chromosomal DNA is made up of Genes To have an idea of the size of this : every million bases take up a linear space of 0,34 mm. So when you take). Toone human cell, uncoil all the chromosomal DNA and put it on a line, you would have 204 cm of DNA (a human cell contains in total 6 x 109 nucleotide pairs to print this information on paper, you need a to know that: one page stores 3100 letters on one side (font courier 12), so 6 x 109 nucleotides, printed on both sides of a sheet, would need pages (you'll have a pile of 120,96 m paper !!!). You'd better start printing immediately... Mitochondria Mitochondria swim around the nucleus. They come exclusively from the mother as they were present in the egg cell at the time of conception. Nucleus A cell has this string of DNA all wound up in its nucleus That strand has 22 pairs of Autosomal Chromosomes-these are chromosome where half of the information came from each parent. It also has on Sex Chromosome which is expressed as XY in a Man and XX in a woman. Therefore, in a man, the Y has to come from the father and the X came from the mother When sperm, which has 22 chromosomes an 1 Y chromosome meets the egg which has 22 chromosomes and an X chromosome they create an embryo that has 22 pairs of chromosomes and either an XX or an XY chromosome. These chromosomes are made up of genes-these genes give the cell information on what to become..A Blue eyed, brown haired tall man amongst other things. The sum total of that information is know as the Genome Source site: The Genome is the total of all your chromosomes
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The Types of Tests Gender Chromosome Y-DNA mt-DNA of Mitochondrial
For Men only Traces paternal lineage Rarely changes/mutates Surname DNA mt-DNA of Mitochondrial For women & men Traces maternal lineage Rarely changes Ancient roots This looks at one chromosome only-the Y chromosome. Since it only happens in males it can only go from father to son In most western countries that means it follows the surname line It rarely changes or mutates.
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The Journey of Ancient DNA
All humans today descend from a group of hominids that started out in Africa. Over 20,000 years they moved to different areas their DNA recombined along the way but the Y DNA and the Mitochondrial DNA changed very slowly so distinct migration patterns can be seen.
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The Types of Tests(cont.)
Autosomal Chromosomes atDNA 22 Pairs--99% shared with all humans-it is made up of nucleotides A T G or C Gene-a region of a chromosome Recombination with each generation Accurate in degrees to about 4 generations. All the chromosomes are made up of genes that are different combinations of ATG or C—each is usually designated by a color The 22 pairs descend in order of size so the first pair is the longest DNA replicates by splitting in half and then replicating itself. In the production of the egg or the sperm the DNA in each sell splits but does not replicate. Therefore when they meet in the nucleus they connect and create a new, unique chromosome. With all that mix and match or “Recombination” this why even though you get half your DNA from your Mother and half from your Father you are not exactly like your sister or brother unless you are an identical twin.
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Chromosomes Notice that the lower the number the bigger the chromosome.
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Before You Test Be open to results and where they lead
If you don’t want surprises, don’t test Test as many members of family as possible Test oldest generations with Autosomal test Privacy-Adoption, Donor privacy, Family Secrets Privacy is a concern for many
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The Companies that Test
Ancestry.com FamilyTreeDNA.com 23andMe.com National Geographic Ancestry- the largest of the databases. Results are easily tied to “paper” research but you have to maintain a membership-not a lot of tools Family Tree DNA- Next largest. Also test Y and Mt DNA. Projects and also the ability to use tools make this very popular 23 and Me – smaller database but growing. Does Medical testing also National Geographic- Studying for Anthropological purposes. Good for Ancient DNA and gives Neanderthal DNA
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How the tests are Analyzed Ethnicity Results Admixtures
Ethnicity is one way to analyze the test but the Ethnicity estimate is just that, an estimate. A certain combination of DNA is present in a population geographically because by nature’s standards we did not move around much until recently. The ethnicity is based on that relationship of certain genes being present in certain locations
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YDNA Projects In theory, the YDNA matches up with surname lines in an ancestral chart. Son to Father to Grandfather etc
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Matching Cousins These are people, who based on their Ancestry Tree and the type of DNA they have may be related to you. But it could be a long way back-
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The Take-Away Paper trail should be wide not deep-4 generations
Test, Test, Test Try to match the test to the problem Test both Sides of the Family Test some more
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DNA as a Tool in Your Family Research Toolkit
Genetic Genealogy By Lynne Holland DNA as a Tool in Your Family Research Toolkit Any Questions
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