I am trying to determine the percentages of shared DNA between various relatives. I need to divide the total shared centimorgans for each into a divisor. Does anyone know the correct value for the divisor?

My father I share 3380.25 centimorgans. However, we have tiny gaps in chromosomes 6, 8, 9, & 12, presumably caused by mutations in me.

I know of another parent/ child comparion in which the shared centimorgans are 3383.52, but they have tiny gaps in chromosomes 1 & 6.

Once I know the divisor, for siblings, I will divide the total shared centimorgans into the divisor; take that result times 2/3 to establish the percentage.

For aunts/ uncles, first cousins & beyond, I will divide the total shared centimorgans into the divisor; take that result & divide it by 2.

This seems to work fairly well. Using the 3380.25 value, my aunt & uncles are all about 25% plus or minus a percent or two; my first cousins are all about 12.5% plus or minus a percent or two.

Timothy Peterman

My father I share 3380.25 centimorgans. However, we have tiny gaps in chromosomes 6, 8, 9, & 12, presumably caused by mutations in me.

I know of another parent/ child comparion in which the shared centimorgans are 3383.52, but they have tiny gaps in chromosomes 1 & 6.

Once I know the divisor, for siblings, I will divide the total shared centimorgans into the divisor; take that result times 2/3 to establish the percentage.

For aunts/ uncles, first cousins & beyond, I will divide the total shared centimorgans into the divisor; take that result & divide it by 2.

This seems to work fairly well. Using the 3380.25 value, my aunt & uncles are all about 25% plus or minus a percent or two; my first cousins are all about 12.5% plus or minus a percent or two.

Timothy Peterman

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