However, in around 15% of cancers, telomeres are maintained by alternative lengthening of telomeres (ALT) mechanisms (Henson et al. 2002).
It follows that unlike in the diploid case, cis-regulated alternative splicing cannot be maintained by selection alone, and that any observed polymorphism for alternative splicing should only be transient.
For instance, it is still unclear if and how alternative splicing can be maintained by selection, or if it is just a transient state before the fixation of a new selectively neutral transcript form by genetic drift.
From equation (1), we find that the conditions under which alternative
An examination of the fitness landscape in a few particular cases is instructive, as it can reveal if selection will promote the fixation of a new variant, or if alternative splicing can be maintained by (balancing) selection, and, if yes, what are the conditions favoring this maintenance.
In both mammalian tumor and yeast cells that lack telomerase, telomeres are maintained by an alternative recombination mechanism.
Once telomerase becomes completely dysfunctional, the gene encoding telomerase could be lost if telomeres are maintained by the ancestral alternative mechanism of homologous recombination.
Telomere length in the remaining 15% of human cancers is maintained by the so-called alternative lengthening of telomeres (ALT) mechanism (Muntoni and Reddel 2005; Cesare and Reddel 2010).
The TAP2 gene portion we analysed herein is subjected to a haplotype-specific alternative splicing event that results in two molecular forms differing at the C-terminus; our data show that the two haplotypes associated with alternative splicing are maintained by balancing selection.
Telomere length is maintained by two known mechanisms, activation of telomerase or alternative lengthening of telomeres (ALT).
