Cytochrome b analyses
Mitochondrial sequences provided information about the haplotypes
present in each area and, together with θST differentiation index, we
were able to indicate which areas have the same source population. We
identified six haplotypes among all sampled populations (GenBank
accession number: XXXXX). Three of them have been sampled on native
range by Austin et al. (2004), two by Kamath et al. (2016) and one by
Bai et al. (2012) on invasive areas of the USA and China. Another three
haplotypes were sampled for the first time in the present work. The
genetic diversity for each site is available on Table 2.
The population differentiation test was significant following the
Benjamini and Hochberg procedure for all comparisons except Minas Gerais
(MG)–Cuba, Brazil–Ecuador, and Singapore–Japan–China (Table 3).
These results suggest that each of these groups have the same native
origin and, for this reason, they were pooled together for the AMOVA.
Belgium and Singapore were also nearly significant (0.05307), but were
not pooled together as Belgium differentiates from the other Asian
countries. AMOVA results showed similar covariance results between
native range areas (Cuba + MG: 18.41 – 20.18; Asian countries: 24.05 –
31.01; Brazil + Ecuador: 17.68 – 26.26; Belgium: 0.00 – 7.87. (Table
4)).
Our phylogenetic analysis recovered topologies congruent with those
reported by Kamath et al. (2016), with USA native west and east clades
as monophyletic groups. Our haplotypes H02, H03, H04 and H06 are
clustered in the western lineage; whereas haplotypes H01 and H05 are
clustered in the eastern lineage.