Concerted Evolution Within the Drosophila dumpy Gene

Abstract

We have determined by reverse Southern analysis and direct sequence comparisons that most of the dumpy gene has evolved in the dipteran and other insect orders by purifying selection acting on amino acid replacements. One region, however, is evolving rapidly due to unequal crossing over and/or gene conversion. This region, called ''PIGSFEAST,'' or PF, encodes in D. melanogaster 30-47 repeats of 102 amino acids rich in serines, threonines, and prolines. We show that the processes of concerted evolution have been operating on all species of Drosophila examined to date, but that an adjacent region has expanded in Anopheles gambiae, Aedes aegypti, and Tribolium castaneum, while the PF repeats are reduced in size and number. In addition, processes of concerted evolution have radically altered the codon usage patterns in D. melanogaster, D. pseudoobscura, and D. virilis compared with the rest of the dumpy gene. We show also that the dumpy gene is expressed on the inner surface of the micropyle of the mature oocyte and propose that, as in the abalone system, concerted evolution may be involved in adaptive changes affecting Dumpy's possible role in sperm-egg recognition.

Structural cuticular proteins from arthropods: Annotation, nomenclature, and sequence characteristics in the genomics era

“…Conserved homologs of “dumpy” have been identified in several insect orders (Carmon et al, 2007). The data are summarized in Table 2 although the complete sequence has not been annotated in any genus except Drosophila .…”

“…I could only identify the pigsfeast region in five Drosophila species, although proteins with long stretches of EGF domains were present in many insects and even in Crustacea and Chelicerata. Those interested in more information are referred to the 178 references listed on FlyBase, especially Carmon et al (2007) and Wilkin et al (2000).…”

“… Final syllable ptera was removed from names of most insect orders. RR-3 is not well defined, so it was not included. Data were obtained from BLAST searches in addition to analyses in: Togawa et al, 2007; Futahashi et al, 2008; Cornman et al 2008, Cornman and Willis, 2009; Carmon et al, 2007, Jasrapuria et al, 2010. id = insufficient data available to record absence; empty boxes indicate that motifs were insufficiently well defined to allow a search. …”

“… Data were obtained from BLAST searches in addition to analyses in: Togawa et al, 2007; Futahashi et al, 2008; Cornman et al 2008, Cornman and Willis, 2009; Carmon et al, 2007, Jasrapuria et al, 2010. …”

Satellite DNAs between selfishness and functionality: Structure, genomics and evolution of tandem repeats in centromeric (hetero)chromatin

“…than between them (Dover, 1982;Rudd et al 2006;Ellingsen et al, 2007). This model has received considerable support from other repetitive DNA elements, such as rRNA genes (Dadejová et al, 2007) and a repeated protein coding gene (Carmon et al, 2007). Effects of fixation are excluded in satellite DNAs from parthenogenetic organisms, due to the lack of bisexual reproduction.…”