Given genotype data from an admixed population and two ancestral populations, ROLLOFF computes the time since mixture using the rate of exponential decay of admixture LD. Specifically, it computes the correlation between a signed LD statistic for a pair of markers and a weight that reflects their allele frequency differentiation in the ancestral populations. The method assumes that samples are unrelated.
For details of the method, refer to Moorjani et al. (2011) and Patterson et al. (2012).
ROLLOFF requires that the input data is available in EIGENSTRAT format. To convert to the appropriate format, one can use CONVERTF program. See README.CONVERTF for documentation of programs for converting file formats.