dat a data frame with nloc+1 columns, the first being the population
to which the individual belongs and the next being the genotypes, one column per locus;
and ninds rows
sex the sex of the individuals
References
Neuenschwander S, Michaud F, Goudet J (2019)
QuantiNemo 2: a Swiss knife to simulate complex demographic and genetic scenarios,
forward and backward in time. Bioinformatics 35:886