A population of humans, isolated for centuries on an
island in the Indian Ocean, exhibits the following phenotypes for
the M N blood group locus.

330 M

  375 MN

295 N

LM and
LN are two codominant alleles at
this locus.
LMLM
alleles give type M blood.
LMLN
individuals are heterozygous.
LNLN
individuals are type N blood.

a)     
Using the Hardy-Weinberg equilibrium, calculate the
expected frequencies of these blood types. Do a chisquare test of
goodness of fit to compare observed and expected values. Is this
population in Hardy-Weinberg equilibrium?

b)
    What might be
going on here? What factors might cause a distribution of genotypes
like this?