ABOUT DNA

DNA research is nowadays available to anyone, at affordable prices. The DNA sample can be ordered on internet and carried out by yourself at home and then sent to a laboratorium. There are three kinds of basic tests in DNA genealogy:

  1. Paternal line (Y-DNA)
  2. Maternal line (mtDNA)
  3. Universal test (Family Finder including X-DNA)

Additional information about DNA studies: https://www.familytreedna.com/learn/ftdna/our-three-basic-tests/


Inheritance patterns

Paternal line (Y-DNA)
Paternal line (Y-DNA)
Maternal line (mtDNA)
Universal test (Family Finder including X-DNA)
Universal test (Family Finder including X-DNA)
Universal test (Family Finder including X-DNA)

Where is DNA located?

The Human Cell
The Human Cell

The 22 autosomes and the sex chromsomes X,Y are located within the cells nucleus. mtDNA is located in the mitochondria, resident outside the nucleus but inside the cell membrane.


What is DNA in detail?

Double Helix - You are a book full of letters.
Double Helix – You are a book full of the letters ATGC.

DNA is the set of genetic instructions for creating an organism. DNA molecules are shaped like a spiral staircase called a double helix. Each stair or base pair is composed of the DNA bases A, C, T, and G. Some segments of these bases contain sequences, like A-T-C-C-G-A-A-C-T-A-G, which constitute individual genes. The total length of chromosome 1-22, X, Y and mtDNA is over 3 billion base pairs and one can simply claim you are a book full of a long sequence of letters formed by previous generations.


How to compare DNA?

To be able to compare the many million base pairs we need a sequenced reference model, a sequenced database. The current human genome reference is known as Hg38. How individual DNA is sequenced is well explained by TED. Simply said – to compare DNA between two or more individuals is to compare blocks of base pairs, the longer block the more closely relative the individuals are.

  • Autosomal DNA – 2867 million base pairs (of which Chr 1 has 245 million base, Chr 2 has 243 mbp, etc).
  • X-DNA – 155 million base pairs.
  • Y-DNA – 58 million base pairs.
  • mtDNA – only about 16569 base pairs.

Learn more about Chromosome 1-22 and 23 (X,Y)

DNA Crossfilter

This is an example utilizing CSV-data, D3 and and Square Crossfilter.
Filter examples (click on the blue hyperlinks in the text below and watch the graphs change):
  • You probably know that you have 23 pairs of chromsomes of which Chromosome 1-22 are autosomes and that sex chromosomes X or Y are chromosome 23 .
  • The chromsome with largest number of base pairs is Chromosome 1, but did you know that Chromosome 22 is not the shortest? It is actually chromosome 21, refer to list below.
  • Did you know that the X chromosome has about 2.7 times more base pairs than the Y chromosome?
  • Try also to brush data directly on graphs

Chromosome 1-22 and 23=X,Y
Longest Block (1 cM ~ 1 million base pairs)
Start location (base pair)
End location (base pair)
Data by Chromosome (- of - rows selected).