Two groups show a gradual increase of variance with distance and contain respectively clay/feldspar related elements and heavy rare earth related elements.
Turnover then increases later in germ line development, resulting in a gradual increase of heteroplasmy variance after birth until the mature oocytes form in the next generation.
In accordance with previous studies (Barton and Turelli 1987; Bürger and Lynch 1995; Jones et al. 2004), Jones et al. (2012) found that, irrespective of the mode of environmental change (gradual, episodic, stochastic), genetic variance increases in the direction of environmental change.
On the other hand, there are approximately two components at the end of the 10,000 time steps (showing a relatively high variance), with a gradual upward trend.
The prey in the predator-prey model experiences a gradual decline in additive genetic variance as a consequence of the moving optimum, and the decline is slightly more rapid in experimental runs than it is in control runs, but otherwise the control runs look very similar to the experimental runs with respect to the dynamics of the additive genetic variance.
In contrast to uncorrelated fluctuations, autocorrelated fluctuations are more similar to the gradual-change scenario, and a population with sufficient genetic variance can follow the optimum and maintain high fitness (Charlesworth 1993; Lande and Shannon 1996; Chevin 2013).
This is especially evident when transitioning from a large variance to a small variance; the change in the subjects' prior was gradual (Fig. 5B).
They coined the term 'demographic constraint' to refer to this situation and calculated 'critical amounts of genetic variance' and 'critical heritabilities' that are necessary to prevent extinction under scenarios of sudden and gradual environmental change.
However, the declines in variances become much slower thereafter, reflecting the slow decay of linkage disequilibrium and the gradual increase in the number of new segregating variants following a population expansion.
