Measuring genetic diversity is one step in conserving wild organisms. To do this, appropriate genetic markers are needed. We are using three types of genetic markers: allozyme proteins, mitochondrial genes, and microsatellite genes.

　

　

While allozymes and mitochondrial genes are often common to a variety of species, microsatellite genes are unique to a group of allied species. This means microsatellite genetic markers, which are tandemly repeated DNA segments (for instance, -CA- or -CAG-), must be sought for each group of allied species. This involves digesting the genome DNA into short fragments, which in turn are inserted into microorganism DNA and amplified; repeated segments are found among the amplified DNA. This work is very laborious requiring much time and laboratory staff.

　

Genetic similarities of the great reed warbler populations among different reed beds of L. Kasumigaura (blue line, male; red line, female; thicker lines indicate higher similarities.)

　

How are such genetic markers used for wildlife conservation? As an example, the great reed warblers are one of the bird species breeding in the reed beds around Lake Kasumigaura. We used microsatellite genes on sex chromosomes to measure the genetic similarities between great reed warbler breeding populations in different reed beds. The results suggested that males bred at reed beds close to their natal sites, but females bred at reed beds some 10 km from their natal sites. This type of information on animal movement is crucial to conservation.

　Genetic markers can be used to prevent invasive species from threatening native biodiversity. Recently in Japan, many insect species have been introduced for agricultural purposes or as pets. These insects may become invasive. If the invasive insects are genetically similar to native ones, genetic introgression may occur through hybridization. Furthermore, the introduced species might be infested with new types of parasites that may be disastrous to the native species. We are using molecular genetic markers to monitor the occurrence of genetic introgression caused by the European bumblebees and tropical stag beetles, which have been deliberately introduced as agricultural pollinators and pets, on Japanese allied species. We are also using a molecular phylogenetic approach with DNA sequences to monitor the introduction of accompanying parasites. Appropriate genetic markers are efficient tools in this research.


Mating between a queen bee of the Japanese native bumblebee, Bombus hypocrita, and a male bee of the introduced bumblebee, B. terrestris.

A male of the Malaysian stag beetle, Dovcus titanus, trying to mate with a femle of the Japanese strain of D. titanus