Estimates \(\theta_{Watterson}=S/a\), where \(S\) is the number of segregating sites in a set of sequences and \(a=1/\sum_i^{n-1} i\).
theta.Watt.dosage(dos,L=NULL)
a ni X nl dosage matrix containing the number of derived/alternate alleles each individual carries at each SNP
the length of the sequence
if L=NULL
(default), returns \(\theta_{Watterson}\), else return \(\theta_{Watterson}/L\)