DNA, Irving

Profile manager: Bill Irving [send private message]

This profile is part of the Irving Name Study.

Have you taken a DNA test?

There is a website where all the Irving DNA results are stored.

Go to this Website to access the excel file.

http://www.clanirwin-dna.org/latest-results

2. Main Results Table for Clan Irwin Surname DNA Study

Click here to download an Excel spreadsheet version of these results.

My own DNA results, from test taken in 2007, are currently on Line 340, entry 229. Position can change with new entries. The only other direct match is Line 339, entry 228; I have not been able to contact them.

Understanding DNA

• (My very simplistic view)

Most Genealogy DNA research is involved with the DNA in the Y-chromosome within males. This is one of the sex chromosomes and is responsible for maleness. All males have one in each cell and copies are passed down (virtually) unchanged from father to son every generation.

To understand where DNA comes from you need to look inside a human cell.

We can see that the cell contains a nucleus within its centre. The nucleus contains the DNA wrapped up in 46 chromosomes. The Y-chromosome is highlighted in purple. Each chromosome is made up of a very long DNA molecule carefully wrapped around proteins.

If the end of the Y-chromosome is pulled the DNA helix can unravel in this model. The familiar double-helix structure of DNA can now be seen. This is made up of two corkscrew-like structures connected by lots of smaller cross-links.

If the double helix is untwisted and flattened a simple ladder-like structure is formed.

When DNA is studied, it is only the rungs of the ladder which are looked at. The ladder is colour coded. These coloured rungs of the ladder are called 'complementary bases'. These bases compliment each other RED to BLUE, YELLOW to GREEN. These are colours are classified:

• Thymine (Blue) T
• Guanine (Green) G
• Adenine (Red) A
• Cytosine (Yellow) C

Thus DNA can be written as:

A G A C G A T C T G T A C C T C T etc.

Because both sides of the ladder match each other, you need only rewrite one side out. When it is said that the Y-chromosome is passed from father to son, this actually means the sequence of letters remain the same.

STR repeats

DNA is often called the 'molecule of life'. Within it are the code words that help build proteins and thus help our bodies to function. However, most of it doesn't encode for anything at all – these regions are currently called 'junk DNA' and these may contain no medical information but may be coded for other reasons. DNA Heritage uses 43 special markers along the DNA strand in these 'junk' regions to read into the genealogy of the person. At these markers, the sequence of bases repeats itself many times (also called STR's – short tandem repeats). As an example,

CTGTCTG TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTGCC

TCTA is repeated 9 times. This STR marker is named 'DYS391', we record: DYS391 = 9

At this particular marker, the number of repeats can be anywhere between 7 and 14. The Y-chromosome is special in that it doesn't undergo 'shuffling' with each new generation. When a new baby is conceived, the chromosomes the baby receives will be a mixture from both mother and father. But the Y-chromosome only comes from the father so the number of repeats in a baby boy will be the same as his father.

Very occasionally these repeats increase or decrease, usually one at a time. That is, a father may have DYS391 = 9 and his son DYS391 = 10. This is called a mutation and happens when the DNA is copied slightly incorrectly within the body. It is worth noting that this is a natural phenomenon and is indicative of Darwin's 'Theory of Evolution' working at a molecular scale! This can help genealogists because it is known roughly how often these changes take place, an estimate of when the most recent common ancestor (MRCA) of the surname lived.

HALOTYPE

When the DNA is tested for many STR's, we obtain a 'haplotype'. This is simply a sequence of numbers from each marker - a bit like a combination to a lock. Using 12 DNA markers, your haplotype could look like this:

Y-DNA STR Markers

• 19 385a 385b 388 389i 389ii 390 391 392 393 425 426
• 14 12 17 12 13 29 24 11 13 13 12 10

DNA laboratories will provide DNA characteristics in 12, 26, 37, 47, 67, up to 100. The cost rises as the number of markers requested rises.

Just 6 makers identify the haplotype most commonly found in Western Europe.

• DYS 19 DYS 388 DYS 390 DYS 391 DYS 392 DYS 393
• 14 12 24 11 13 13

www.yhrd.org. database contains haplotypes for the world DNA project using 11 markers. OR http://www.eupedia.com/europe/european_y-dna_haplogroups.shtml

Genetic genealogy can substantiate the known, paper genealogy and help prove that two or more individuals, with the same surname, are connected by a common ancestor. Estimating when that common ancestor actually lived is left down to mathematics and statistics. Studies show that although a mutation at any particular marker is a random event, it is expected to change roughly once every 500 generations. It is like a ticking clock, although this DNA clock doesn't always chime right on time. Using 43 markers, would expect to see a single mutation once every 12 generations (500/43 = 11.6) - however your paternal DNA may have changed more recently, or is about to do so in a couple of generations time. This simply means that the further back the MRCA (most recent common ancestor), the more mutations are expected. If we have an exact match on all 21 markers, the average time when the MRCA lived is only 8.3 generations ago; 37 markers would bring this down to approximately 4 generations.

How many mutations/mismatches are needed to exclude a relationship? The more mutations equates to a more distant relationship. With 21 markers, 2 mutations between haplotypes is a very much borderline result, but 3 mutations would usually exclude the possibility of a relationship between two individuals.

There are some limitations with DNA testing, and it should only be used in conjunction with the existing genealogy. Therefore the conclusions given above are not absolute certainties, but the DNA evidence does give very strong support for such conclusions.

Haplogroups. – Deep Scan Genealogy

Haplogroups often indicate a specific area. R1b is the most common Y chromosome for Europe. The different haplogroups are based on the mutation of one letter to another in the DNA strand: T become A. As man has migrated around the world over time, these haplogroups can be used to trace their paths. Very roughly this is what occurred:

• Out of Africa 100,000 BC
• Yemen 80,000 BC
• MALAYSIA 75,000 BC
• AUSTRALIA 60,000 BC
• EUROPE 50,000 BC
• SIBERIA 20,000 BC
• NORTH AMERICA 16,000 BC

Europe 18,000 BC 3 groups exist :

• SPAIN R1b
• BALKANS I
• EASTERN EUROPE R1a

Europe 12,000 BC R1B Atlantic seaboard extends as far as Scotland.

• I Central Europe and Scandanavia
• R1a Eastern Europe, Central Asia, and India.

Europe 8,000 BC Neolithic hunters/agriculturalists move in from the Middle east

• E3b
• F,
• J2
• G2

Europe 4,500 BC Central Asian group N3 moves into Northern Europe (Fino/Urgric)