3.2 | Effective population size and interspecific gene
flow
Based on MSMC analyses, the
effective population size for both François’ langur and White-headed
langur appears to have decreased moderately since their divergence at
approximately 290,000 years ago (95% HPDI: 180-590 Kya) (Figure 6).
The effective population size was
the lowest at 10 Kya, and then increased sharply beginning
~10 Kya for both species. In the case of François’
langur, its effective population size increased more quickly than
did the effective population size of White-headed langur during the past
10 Kya.
The best-fitting model for the speciation of François’ langur
and
White-headed langur was Model 3, indicating periodic interspecific
contact following their initial divergence (Supporting Information Table
S3). Secondary contact began ~140 Kya (95% HPDI: 48 Kya
-300 Kyaand ended at ~12 Kya (95% HPDI: 1 Kya -26 Kya).
In addition, gene flow between these two species appeared to be
directional that was higher from François’ langur to White-headed langur
than inverse. The current effective population size (Ne ) of
François’ langur and White-headed langur is estimated at
~50,487 and ~4,177, respectively (Table
2; Figure 4).