The production of β-carotene in yeast can be increased by duplication and inversion of crtI gene in the constructed pathway18 (Fig. 2).
However, moderate genome increase, e.g., by duplication of parts of the genome, or by recombination, can be fixed via genetic drift in small populations [ 9].
Nevertheless, the proportion of gene increase by tandem duplication within clusters was on average estimated to be as large as 31% (see supplementary table S13, Supplementary Material online for details).
Teichmann, S.A. & Babu, M.M. Gene regulatory network growth by duplication.
In vertebrates, the genes number in E2F1-6, RB, DP and E2F7/8 families increased by genes duplication events, these duplications occurred no later than tetrapoda and teleostei divergence.
We identified the core promoter sequence (222 bp) comprising two SP1 sites and could show a further increase in activity by duplication of this minimal sequence.
The gray pawn hypothesis suggests that if the number of functional genes in a family drops too much, selective pressure increases to gain new genes by duplication and divergence, and gene number increases by selective retention of new duplicates.
† The original cohort of 1340 subjects was increased by progressive duplication to 2, 4, 8, 16, and 32 times its original size.
The orbits in PCA space, which represent expression profile changes, were similar except for strain C. The reason for this exception might be that strain C has an approximately 200 kbp region in the genome that was duplicated (discussed below), and the expression levels of genes in this region were increased by this duplication.
We also found that genes expressed tissue-wide are located in the centromeric region, whereas the tissue-specifically expressed genes are located towards the telomeric end of the H2-T region where the number of genes has been increased by local duplication.
And then, in bryophyte, the family member of P. patens has increased to 37 by duplication.
