Grade of Membership Sibpairs analysis example
Grade-of-membership sibpair linkage analysis*
Number of observations I = 578 sibling pairs in IDDM** families
30% males, 20% females, 50% different sex,
53% both affected, 43% one affected, 4% neither affected
Number of variables J=8 marker loci ( D14859, D148128, D14S67, CCC1, AFM848, D14S81, D14S45, D14S51 )
Number of categories L=3 ( 1 - no alleles in common at the marker locus,
2 - one allele in common, 3 - both alleles identical )
Number of pure types K=3 selected by Akaike’s information criterion
Number of estimated parameters
(K-1)*I+K*(L-1)*J
2*578+3*2*8 = 1156
*Grade-of-membership sibpair linkage analysis maps IDDM11 to chromosome 14q24.3–q31.
Corder E., Woodbury A., Manton K., Field L. Ann. Hum. Genet., 65(2001): 387-394
** IDDM - insulin dependent diabetes mellitus
