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DNA STUDY

Everytime you buy from Amazon, please click on the link shown to the left and the Hawgood family DNA study will receive a small fee which will fund more tests.

We have two useful calculators available

1) Calculator to show the most likely statistical generation gap based on the number of mutation and the mutation rate, and uses simple probability presented in a tabular format, rounded to the nearest number of generations.

2) Calculator to show the most likely number of mutations for any given set of markers, generation gap and average mutation rate. The formula uses a standard probability mechanism, which looks more complicated than it actually is :

Where :

P = the mutation rate (eg quoted as 0.0033 and not a percentage at 0.33)

T= the total number of markers tested multiplied by the number of generations x the number of people in the comparison

t = the number of markers that have mutated

! = factorial, for example 6! is the as 6x5x4x3x2x1

To work out the probability of 2 mutations in 44 markers over 7 generations, between 2 people using a mutation rate of 0.33%:

P = 0.0033

T = 44 x 7 x 2 = 616

t = 2

Plugging the numbers in to the equation :

= (1-0.0033)^(616-2) x 0.0033^2 x (616!/614!)/2!

= 0.131394 x 0.00001089 x (616x615)/(2x1)

= 0.271 or 27.1%

Note that if you try to calculate 616!, your calculator or computer will find this number to big to handle. We used a short cut above used to calculate 616!/614!, which is the same as 616x615. To calculate 64!/60!, this is the same as 64 x 63 x 62 x 61. Don’t bother with long hand however, just use the Calculator. Below is an example of 2 people being compared over 4 generations, comparing 63 markers and using a mutation rate of 0.0041, or 0.41%. (a screen shot is below). There are 504 opportunities to see a single mutation and the most likely outcome is to see 2 mutations, at a 27% chance.