  Statistical models for genetic linkage analysis of k-locus diseases are
k-dimensional subvarieties of a (3^k-1)-dimensional probability simplex. We
determine the algebraic invariants of these models with general characteristics
for k=1, in particular we recover, and generalize, the Hardy-Weinberg curve.
For k = 2, the invariants are presented as determinants of 32x32-matrices of
linear forms in 9 unknowns, a suitable format for computations with numerical
data.
