Interpreting kinship estimates

[Naomi Brunjes]

Does the kinship estimates from the snpgdsIBDMLE() function use the same scale as the gl.grm() function in dartR? 

I.e.:

#0.5 = Identical twins/clones/same individual
#Sibling/Parent-Offspring | 0.25 | (0.204, 0.296)
#Half-sibling | 0.125 | (0.092, 0.158)|
#First cousin | 0.062 | (0.038, 0.089)|
#Half-cousin | 0.031 | (0.012, 0.055)|
#Second cousin | 0.016 | (0.004, 0.031)
#Half-second cousin | 0.008 | (0.001, 0.020)
#Third cousin | 0.004 | (0.000, 0.012)|
#Unrelated | 0 | - |

[Jose Luis Mijangos]

Hi Naomi,

Yes, the kinship estimates from the snpgdsIBDMLE() function use the same scale as the gl.grm() function in dartR. 

Two alleles are identical by descent (IBD) if they are identical copies of the same ancestral allele in a base population. Relatedness is the proportion of alleles shared between individuals that are IBD. Kinship is the probability that two alleles, one taken at random from each individual, are IBD (Wang, 2022). Kinship considers half the genetic information because it looks at the probability that one individual inherits a particular allele from a common ancestor shared with another individual. Therefore, kinship is equal to half of relatedness.

Wang, J. (2022). A joint likelihood estimator of relatedness and allele frequencies from a small sample of individuals. Methods in Ecology and Evolution, 13(11), 2443-2462. 

Cheers,

Luis