Selection on Length Mutations After Frameshift Can Explain the Origin and Retention of the AP3/DEF-Like Paralogues in Impatiens

Abstract

Evolution of class B genes through gene duplication has been proposed as an evolutionary mechanism that contributed to the enormous floral diversity. Frameshift mutations are a likely mechanism to explain the divergent C-terminal sequences of MIKC gene subfamilies. So far, the inferences for frameshifts and selective pressures on the C-terminal domain are made for old duplications for which the exact selective pressures are obscured by evolutionary time. This motivated us to study an example of a recent duplication, which allows us to consider in more detail the selective pressures that are involved after duplication. We find that after duplication and frameshift of Impatiens class B genes, the individual codons show no evidence for adaptive selection. It is rather the length of the C-terminal domain that either is strictly conserved or varies strongly. This suggests a role for the length of the C-terminal domain in the retention of duplicated genes.

Breeding systems in Balsaminaceae in relation to pollen/ovule ratio, pollination syndromes, life history and climate zone

“…Total genomic DNA was isolated from silica‐dried leaf material using a modified CTAB protocol (Doyle & Doyle ) optimised for Impatiens (Janssens et al . , ). The two nuclear AP3 / DEF homologues ( ImpDEF1 , ImpDEF2 ) and the plastid atpB‐rbcL intergenic spacer were amplified following Janssens et al .…”

The PI/GLO-like locus in orchids: Duplication and purifying selection at synonymous sites within Orchidinae (Orchidaceae)

“…Evolutionary analyses of class-B MADS-box genes (AP3/DEF-like and PI/GLO-like) have revealed positive selection after duplication, occurring during the evolution of angiosperms (Becker et al, 2002;Hernandez-Hernandez et al, 2007;Janssens et al, 2008;MondragonPalomino et al, 2009). Recently, relaxation of purifying selection was detected within some class-B MADS-box genes from orchids .…”

Portrayal of Impatiens nzabiana (Balsaminaceae): a Morphological, Molecular and Biogeographic Study of a New Gabonese Species

“…Primers and temperature profiles used for the amplification of atpB-rbcL , ImpDEF1 / ImpDEF2 and ITS follow Janssens et al (2006Janssens et al ( , 2007 and White et al (1990) , respectively. DNA extraction, PCR amplification, sequencing, sequence assembly and alignment were followed as described by Janssens et al (2008) . All sequences obtained were submitted to GenBank (Appendix 1) and the data sets and the representative trees are deposited in TreeBASE (study number S10796).…”