| 研究概要 |
In the course of my preliminary work, I found evidence for epigenetic sex determination in the little fire ant Wasmannia auropunctata, in an invasive population in the Galapagos Islands.
The original goal behind my research project was to examine mechanisms that can facilitate biological invasions, despite the high cost of inbreeding due to a single-locus sex determination system. While waiting for the Galapagos permits, we have been looking at sex determination mechanisms in a Japanese ant species, Vollenhovia emeryi, which has the same unusual reproductive system as W. auropunctata where queens and males reproduce clonally (Ohkawara et al. 2006). Workers are produced sexually, but are sterile. This sort of clonal reproduction system was proposed as an adaptation to avoid inbreeding depression (Mikheyev et al. 2009). Taking advantage of rare sexual production by queens of V. emeryi, we made experimental backcrosses, creating inbred lines, which produced a 3:1 ratio of workers to diploid males. This suggested the existence of not one, but two sex determination loci, which would make this species resistant to inbreeding. We confirmed the existence of two loci by mapping RAD-tags in this cross and confirming two QTLs on different linkage groups. These results show that (a) the existence of alternative sex determination modes in social insects and (b) that ants with the unusual reproductive system shared by W. auropunctata and V. emeryi are able to avoid costs of inbreeding.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
4: 遅れている
理由
Since receiving the grant, much of the time has been spent waiting for permits, which have just been authorized last April. I have just now received permits for the planned Galapagos fieldwork, which will be conducted as soon as possible. The process of obtaining collecting permits has taken over one year. On the other hand, we have accomplished the major goal of the original study using a different species.
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