Where did you get these numbers? Seems impossible to me that such a low number was able to sustain dispersed groups of modern humans over a global area. By that time some modern humans had already left Africa and dispersed into Asia.
"It was no coincidence that in the eastern Mediterranean at the change from OIS5 to OIS4, i.e. just after the Toba YTT event, the Afro-Asian biotic community was abruptly replaced by a palaeoarctic one, including the already cold-adapted Homo neanderthalensis (ref. Tchernov E. 1992a; Ambrose S.H. 1998)."
"Estimating how low the number of members of the species Homo sapiens could have been to account for today's human genetic uniformity involves a number of variables that are anything but clear-cut. It has been estimated that only 40 to 600 females (which translates into a total population of less than 3,000 persons; Harpending H.C. et al. 1993) came through the bottleneck. Another estimate arrived at 500 to 3,000 females (ref. Rogers A.R. 1993) and yet another at 1,000 to 4,300 individuals (Ayala F.J. 1996; Takahata N. at al. 1995). The highest estimate so far has 10,000 females of reproductive age as the minimum (ref. Ambrose S.H.. 1998). Even if the highest estimate is accepted, we are talking about the entire human race numbering no more than the population of one small country town today."