Figure 1 . Map showing the population localities and the sex
ratio of each population. A population code (p1–p33) is given to each
population. Pie-charts show sex ratio investigated by sex check PCR or
crossing experiments: females are represented in black, males are
represented in white, and samples from which both female and male
markers amplified in the sex check PCR are represented in grey.
Pie-chart sizes are proportional to the corresponding sample size. TS,
Tsugaru Strait; KC, Kuroshio warm ocean current; TC, Tsushima warm ocean
current; OC, Oyashio cold ocean current; ESC, East Sakhalin cold ocean
current.
Figure 2 . Cox 1-haplotype network. Population codes
[1–33 (without ‘p’)] are given to the haplotypes of Japanese
samples. Sampling regions are represented as different colors. For the
samples from Japan, samples from sexual and parthenogenetic populations
were represented in different colors. Each colored circle represents a
haplotype and its size is proportional to its frequency, whereas white
circles represent hypothetical unsampled haplotypes. White squares
represent median vectors. Haplotypes indicated by arrowheads were found
in 6–45 samples of which sex was identified, but none of these samples
were identified as male (female or samples having both female and male
markers).
Figure 3 . Maximum likelihood (ML) tree based on the nuclearcetn -int2 (604 bp). Numbers on branches indicate bootstrap
percentage from ML analysis. Only bootstrap percentages ≥ 60% are
shown. The labels of samples Japanese from parthenogenetic populations
are indicated in red color, those from Japanese sexual populations are
in black, and those from Argentina and Europe are in blue. Asterisks are
given to the samples from the Sea of Japan coast (p1–p16), and stars
are given to the samples from the Tsugaru Strait and Kyushu (p6, p16,
p17, p30, and p31). Arrowheads indicate the two haplotypes found in
samples from p24 and p27.
Figure 4 . Histograms showing genetic distances between samples
based on the haploid dataset. (a) Genetic distances in parthenogenetic
populations. (b) Genetic distances in sexual populations. The threshold
distances (10) to recognize clonal lineages is indicated by broken
lines. Samples from Europe and Argentina are included in the histogram
for parthenogenetic populations. Note that, in the actual calculation in
‘assign clone ’ function of GenoDive, the dataset was not
separated into sexual and parthenogenetic populations.
Figure 5 . Result of the STRUCTURE analyses based on the diploid
dataset when K = 2 and K =5. The frequency of each cluster
in each sample is shown by the bar plot. Sampling region in the Japanese
Islands are shown above the bar plot, and population codes [1–33
(without ‘p’), ARG: Argentina, EUR: Europe; parthenogenetic populations
from Japan are indicated in red] are shown below the bar plot. (a) The
genetic clusters estimated in all runs at K = 2; (b) The genetic
clusters estimated in five of 10 runs at K = 5; (c) The Neighbor
Joining tree for the five clusters at K = 5 shown in (b). Color
for each cluster is consistent in the bar plot of (b) and the NJ tree.
Figure 6 . Result of the PCA based on the diploid dataset
showing the locations of each individual on the first three principal
components (PC1–PC3), which describe 54% of the genetic variation. (a)
Plot for the first and second PC. (b) Plot for the first and third PC.
In Sampling localities of each Japanese population are shown in the map
of Japan shown above the charts. Colors for each population are
consistent in the PCA plots and the map.
Figure 7 . The NeighborNet tree based on the diploid dataset,
showing the polyphyly of parthenogenetic populations. Labels of
population codes of parthenogenetic populations from Japan are indicated
in red. Japanese population are roughly color-coded according to the
regions: the Pacific coast (deep blue), around the Tsugaru Strait
(orange), around Kyushu (green), and the Sea of Japan coast (rose).
Figure 8 . Results of the GCMS analyses of the volatile
compounds released from gametes: extracted ion chromatograms = 148–149m/z . The compounds predicted as sex pheromones were detected with
high intensity at around 12.1 and 14.6 min from female gametes of a
sexual population (p15; asterisks), not from those of parthenogenetic
population p28. For the first compound, the fisrt candidate was
ectocarpene and the second candidate was the cis-trans isomor of
ectocarpene. For the second compound, the first candidate was
ectocarpene and the second candidate was
(3E ,5E ,8E )-1,3,5,8-undecatetraene.