A number of mechanisms can generate duplicate copies of genes, ranging from single gene duplications to regional and whole genome duplications [ 1- 3].
Recently several authors have proposed theories in which a two-gene ProtoHox cluster duplicated and the resulting clusters later independently underwent tandem gene duplications to form the extant Hox and ParaHox clusters [41], [51].
Thus, the LGV duplication exemplifies the property of duplications to further amplify; while LGI duplication shows that a duplicated region can revert back to a normal copy number.
Thus, to compare structural divergence among different modes of gene duplication, we restricted WGD duplicates to those retained from the α event, and transposed duplications to those that occurred after Arabidopsis-Brassica divergence (<16 Mya).
The preferential post-transcriptional regulation of duplicated R-genes by miRNA can be proposed as part of a functional diploidization process in response to duplications to maintain a perfect dosage balance regarding the product of R-genes duplicates.
Ancestral DNA sequences coding for 2TM-like proteins underwent nucleotide "edition" and gene duplications to generate the 6TMs.
These findings were interpreted as follows: a species developed an ancestral eyespot with undefined ancestral photoreceptors and opsin which underwent cell and gene duplications to give rise to rhabdomeric and ciliated photoreceptors with r-opsin and c-opsin, respectively.
That supports the notion that these genes "have diversified throughout evolution from their ancient duplications to perform important, specific, diverse roles in mammal cognition in behavior".
Whether to attribute such duplications to the HG or to be part of the planum temporale is discussed controversially in the field [15], [46].
Based on the relative contributions of tandem versus segmental duplications to the FBX gene repertoire, we found three different FBX gene expansion patterns (Figure 8A).
In addition, an unidentified haplo-insufficient locus lies close to this cytogenetic region [9] necessitating the use of duplications to maintain stocks carrying deficiencies uncovering the region of interest.
