DNA Basics

DNA is the blueprint from which your body is built. The DNA of all humans is virtually identical and is the reason we have five fingers and toes and two legs and arms. It determines where those parts are fastened to our body and where our vital organs are placed. The very slight differences in our DNA determine the slight differences we see in each other — whether we’re short or tall, the color of our eyes and hair, the size of our feet, the shape of our sinuses, tongue and voice box which determine how our voice sounds, etc.

We use these slight differences to tell one another apart, and we use the slight differences in our DNA to tell which family groups we belong to.

There are four basic types of DNA used in genealogical research:

• Three of them are located within the nucleus of our cells:
  • 1. Autosomal DNA — 22 pairs of rope-like chromosomes. This is “recombinant” meaning a person gets a portion of it (typically 1/2) from each parent.
  • 2. Y-chromosome DNA — 1/2 of the 23rd pair of chromosomes. This is passed from a father to his son. Both Y-STR and Y-SNP data can be used, Y-STR providing information on more recent differences and Y-SNP providing information on ancient family lines.
  • 3. X-chromosome DNA — like the autosomal, it is recombinant, but men do not get any of their X-chromosome from their fathers, so it provides a “lopsided” view of one’s ancestry as opposed to autosomal DNA.
• The fourth is located outside the cell’s nucleus
  • 4. Mitochondrial DNA. It comes only from the mother and is passed to her children.

We inherit random portions of our autosomal and X-chromosome DNA from both of our parents, whereas the Y-DNA and mtDNA come from only one parent.

In traditional research, we search for something unique that can be used to define or identify an ancestor. A bunch of papers mixed together in a box at the courthouse is meaningless without a name or place or some other tidbit of information that we can use to help us in our research.

DNA is the same way. We need to be able to identify which parent contributed it if it’s to be used to trace ancestry. Autosomal DNA can become like the mess of papers in the box — it has been randomly mixed up and it is difficult to tell which parent contributed it. It’s of little use in any research beyond three or four generations, five at most. On the other hand, mtDNA does not share anything with the father’s DNA, so it represents the mother’s lineage (maternal line). The Y-DNA does not share anything with the mother’s DNA and it represents the father’s (paternal) line. The fact that both mtDNA and Y-DNA are passed unchanged from parent to child make them ideal for tracing ancestry. The slight changes which occur when a mistake is made in copying the DNA from parent to child become the distinguishing characteristics for family branches.

Unfortunately mtDNA changes too slowly to provide very much useful data for tracking recent ancestors. It is better suited to researching ancient ancestral ties.

Y-STR DNA changes more rapidly than mtDNA does and thus provides the most useful information for genealogical DNA research. The Cloud DNA Project is a Y-DNA (STR) project.

• Cloud DNA Home.
• Why DNA - Ways in which DNA can help genealogical research.
• Goals - The reasons we're using this tool and what we expect from it.
• Guidelines - The procedures used and how to participate.
• FAQ - Answers to the most common questions about the use of DNA in genealogy.
• DNA Basics - A brief introduction to DNA and how it is used in genealogy.
• The DNA Lab - Information about the testing service that performs our DNA tests.
• The DNA Test - How the DNA sample is taken and what is done with it.

• We need You - Why we need you to join the Project.
• Project Rules - The simple requirements for successful participation.
• REGISTRATION - The Registration Form.
• Submit Pedigree - Submit your Pedigree Information.

• What to expect from your Y-DNA test:
  • Understanding - A guide to understanding the Project results.
  • Interpretation - Our best analysis of what the results mean.
  • Pedigree Chart - The lineages of our test participants.

• Cloud DNA Project Results:
  • Cloud DNA at Family Tree DNA.
    
  • Cloud DNA "Activity Feed" (aka "bulletin board" – must log in).
    
  • Cloud DNA Results.
  • FTDNA Y-STR Results 'Colorized'.
  • FTDNA Y-SNPs.
  • FTDNA Y Map.
  • FTDNA mtDNA Results.
  • mtDNA map.

• Interesting and informative web sites.

• Contact – Email the Project Administrator with your questions.

• * Anyone descended from a Cloud family can join the Project.
• Participation is not restricted to Cloud Family Association members.
• * The Y-STR CLOUD Surname Project can only use data from men who are a descendant through the male-only line of a CLOUD male ancestor.
• Your pedigree is required to facilitate comparison and analysis of your data.
• See "Project Rules" for eligibility.

---

Member International Society of Genetic Genealogy (ISOGG).