Ailanthus altissima is a tree species native to China and has been naturalized in many countries. Although there is basic knowledge on its ecological characteristics, little is known on its genetics of introduced populations. Hence, we investigated the distribution of chloroplast haplotypes of A. altissima in Japan with DNA sequencing.

We analyzed 4 natural populations and 72 populations in China and in Japan, respectively. Six haplotypes were identified by ca. 2400 base sequence of cp DNA. There were close genetic relationships between haplotypes B and C and among haplotypes D, E and F. Haplotypes B, C, E and F were found in China and haplotypes A, B and D were found in Japan. Among 412 trees analyzed, 218 of A from 50 populations, 190 of B from 42 populations, and 4 of D from one population were detected in Japan. The admixture of “A and B” and “A, B and D” were found from 20 populations and 1 population, respectively. While each Chinese population was composed of genetically close trees in haplotype, some Japanese populations were composed of trees having a few genetically distinct haplotypes. Our results show the origin of introduced A. altissima was limited to a few genetically distinct maternal groups in Japan.