Inbreeding in a European ancestry sample from the contemporary UK population

Re:Inbreeding in a European ancestry sample from the contemp... by iguy on Sunday October 06, 2019 @03:46PM (#21174573)

And defines this to mean double-first-cousins and closer (perhaps this is standard). Also, as far as I could skim, this is the prevalence today, rather than an estimate of long-run prevalence.

They must surely have data on simple first cousins, but it didn't jump out at me.

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Re:Inbreeding in a European ancestry sample from the contemp... by blueblimp on Sunday October 06, 2019 @06:35PM (#21175677)

For traits, the effect on non-double first cousins can be linearly approximated, which (as far as I know) is a good approximation for inbreeding depression.

For example, taking Fluid Intelligence Score (basically how smart you are), in Table 3, its extrapolated effect size is -3.43, so:

First cousin (relationship coefficient 0.125, inbreeding coefficient 0.0625) would give -0.214 to FIS. To put that in context, for medication, that would be considered a small effect size. So inbreeding at that level is a bit like taking a stupid pill.

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Re:Inbreeding in a European ancestry sample from the contemp... by wyattpeak on Sunday October 06, 2019 @06:36PM (#21175685)

Simple first cousins have a coefficient of relationship of 0.125, which is below the threshold considered in the paper.

Received wisdom is that a coefficient below 0.25 doesn't cause serious deleterious effect. I have no idea if that's well supported, but I imagine it's relevant to why it wasn't studied.

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Re:Inbreeding in a European ancestry sample from the contemp... by azernik on Monday October 07, 2019 @01:32AM (#21177828)

The motivating force for this definition is uncles/aunts and closer; it just so happens that double-first-cousins have the same genetic relatedness as double first cousins.

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