It is difficult to quantify how much rate variation has contributed to the difference between mammals and non-mammals.
Although much strain variation has been identified, these markers have not been clearly linked to host tropisms except for 16S rRNA and the US Ap-variant 1 (Ap-V1).
Where appropriate, we then compare these values to census counts (N) from both populations to determine how much genetic variation has been retained over the recent range contraction.
Much of this variation has a heritable component [ 25, 27- 30].
Much of this variation has remained unexplained (Hodgkinson and Eyre-Walker 2011).
Much of this variation has been usually attributed to adaptation to edaphic and climatic factors [ 35, 38].
The size of the effects must be detected and the noise of the process (how much variation it has) will dictate how much replication is needed.
In addition to spatial variations of the carbon-14 level, the question of temporal variation has received much study.
Much higher standard deviations of the FCA-scores among the oldest compared to present-day samples showed that the distribution of genetic variation has been much wider historically.
Much of the assertion that 15q25 variation has a direct effect on lung cancer risk rather than solely being a proxy for smoking comes from the observation that the lung cancer association is not accounted for by the relationship with smoking quantity.
