Wingless (Wnt1 gene family)
The wnt family of protein coding genes are involved in early embryogenesis in insects and vertebrates (e.g. Uzvölgyi et al. 1988; Rijsewijk et al. 1987). At least a dozen subfamilies have been identified in this large and variable gene family (Sidow 1992, Schubert et al 2000). Of these subfamilies, wnt-1 has been shown to be phylogenetically informative at a variety of levels, including among phyla of metazoan animals (Schubert et al. 2000), among Hawaiian carabid beetles (Cryan et al. 2001), and among and within Lepidopteran families (Brower and DeSalle 1998, Brower & Egan 1997, Brower 2000, Campbell et al 2000, Wahlberg et al. 2003). A recent study of phylogenetic relationships within the stalk-eyed flies (family Diopsidae) concluded that, of the six genes analyzed, wingless proved to be the most useful (in terms of congruence, data decisiveness, and bootstrap support; Baker et al. 2001).
In a preliminary evaluation of the wingless gene for relationships among the bee families, subfamilies and tribes, we used primers developed for Lepidoptera (wg1a and wg2a; Brower and DeSalle 1998). These primers non_specifically amplified two to three wingless paralogs in most bee and spheciform taxa. Two paralogs differed in size and could be separated on low melting point agarose gels. When paralogs were similar in size we used PCR product cloning (T/A cloning) to isolate and sequence alternative paralogs. We characterized a total of three wingless paralogs in bees that could be separated unambiguously based on small or large indel mutations. The three paralogous copies in bees clustered unambiguously into three different wingless gene families. Our most common paralog is in the wnt-1 family. Based on these wnt-1 sequences, we designed a new forward PCR primer (bee wg For) that specifically amplifies 450 bp of the wnt-1 paralog in a variety of ST bee families and sphecid outgroups. Preliminary phylogenetic analysis of 65 halictid wnt-1 sequences recovered subfamilies, tribes and genera that have been well supported by morphology and other single-copy nuclear genes (Danforth et al. 2004). Sedonia Sipes (Southern Illinois University, Carbondale) is expanding the wingless data set using 5' RACE to amplify and sequence an upstream portion of the gene in a broad sample of ST bees. Currently available primers are listed in the pdf file below.
The Drosophila wingless sequence is available on GenBank as accession number J03650 (Uzvölgyi et al. 1988).
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Gene Information: |
Wingless primer information (.pdf file) |
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