Looking at the basics for DNA testing
FOR GENEALOGY
By Gail Riddell for
New Plymouth - NZSG
22 May 2016
There are three main genealogy tests
• Autosomal DNA (atDNA) any one can test
this. (Includes the X chromosome).
• Mitochondrial DNA (mtDNA FMS) the
direct maternal female line.
• Y Chromosomal DNA (YDNA) the direct
paternal male line. (The ‘Y-front’ brigade)
The atDNA test (autosomal
chromosome)
• There are 46 chromosomes within each human.
• 22 come from your mother and 22 come from your
father – all mixed and muddled.
• The 23rd chromosome is the gender chromosome (X
& Y).
• Males receive an X from mother plus a Y from father
(22 pairs + 2 = 23 pairs or 46 in total).
• Females receive an X from mother plus an X from
father (22 pairs + 2 = 23 pairs or 46 in total).
The basic parts of a cell
mitochondria
A graphic of atDNA for genealogy
GG
GF
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Dad
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Mum
You
© Louise Coakley
Genie1.com.au
The mtDNA test (mitochondria)
• The mitochondria are not chromosomes – they
surround the nucleus of the cell in which the
chromosomes exist.
• Everyone receives mtDNA from only their mothers.
• Males cannot pass their mitochondria on to any of
their children.
• The mitochondria are the ‘powerhouses’ for each cell.
mtDNA Graphic
G
G
G
M
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You
GG
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Sister
Mum
GG
GM
G
GM
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GU
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Uncle
GG
Aunt
Great
Aunt
1st
Cousin
2R
Aunt
1st
Cousin
1R
2nd
Cousin
1R
1st
Cousin
2nd
Cousin
3rd
Cousin
GM
Uncle
Brother
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Dad
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GF
3
G
Cousins can be male or female as lon
as their mother is a direct line femal
The YDNA test (Y chromosome)
•
•
•
•
This exists only in males.
Every father passes his “Y” intact to his son.
His son then passes it to his son and so on...
Females cannot receive this.
Y DNA Graphic
3
G
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GU
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GU
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1st
Cous
3 Rem
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Uncle
2nd
Cousin
2 Rem
1st
Cousin
2 Rem
Great
Uncle
Great
Uncle
3rd
Cousin
1 Rem
2nd
Cousin
1 Rem
1st
Cousin
1 Rem
1st
Cousin
1 Rem
Uncle
4th
Cousin
3rd
Cousin
2nd
Cousin
2nd
Cousin
1st
Cousin
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Dad
Mum
Male
Male
Male
The XDNA test (X chromosome)
The X & Y are known as the sex
chromosomes
• The X exists in both males and females.
• Females receive two Xs; males receive one X.
• Every mother passes one copy of their X to each of their
children.
• Every father passes one copy of his X to his daughters only.
• The X results are automatically included in any atDNA test.
X Chromosome – female graphic
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GF
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YX
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YX
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YX
YX
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YX
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YX
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`
GF
YX
Dad
GM
GF
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Mum
Female
© Louise Coakley
Genie1.com.au
X Chromosome – male graphic
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Dad
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YX
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Male
YX
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YX
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YX
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YX
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Mum
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GM
`
Contact details
• Gail is [email protected]
• FTDNA is www.familytreedna.com
• The NZ DNA project
https://www.familytreedna.com/groups/new-zealand/about
• 23andMe is www.23andme.com
• An excellent glossary is found at
www.familytreedna.com/learn/glossary/