Figure Legends
Figure 1 . Studied hybrid region. A) Map of the 20
sampled populations. Dark blue circles denote allopatric I.
elegans , yellow circles denote allopatric I. graellsii . Inside
of the Spanish hybrid region, dark blue, yellow and orange circles
denote I. elegans dominant, I. graellsii dominant or both
species, respectively (1 indicates north-west populations, 2 indicates
north-central populations and 3 the Balearic population). B)Zoom of Spain, showing the
geographic distribution of I. elegans over time, from 1888-1979
(8 provinces, dark-grey), 1980-1999 (13 provinces, medium grey) and
2000-actuality (12 provinces, light grey). White colour indicates onlyI. graellsii populations (15 provinces).
Figure 2. Strength of
mechanical barriers to reach the copula in A ) north-central
hybrid region (colonized by I. elegans at least 14 years ago),
and B) north-western hybrid region (colonized by I.
elegans at least 41 years ago). INTROGRESS estimates of ancestry
proportion (HI) and heterospecific ancestry (HET) by using the 381 fixed
SNPs for I. elegans , I. graellsii and hybrids fromC ) north-central hybrid region and D ) north-western
hybrid region. F1 and F2 hybrids
(orange) occupy the apex of the triangle. Backcrosses to I.
elegans introgressed I. elegans and pure I. elegans(light blue). Backcrosses to I. graellsii , introgressed I.
graellsii and pure I. graellsii (light blue).
Figure 3 . INTROGRESS individual and class proportions estimates
of ancestry proportion in A ) north-central hybrid populations,
and B) north-west hybrid populations. Populations were assigned
to three qualitative measures depending on the frequency distribution of
the different hybrid classes: unimodal hybridization pattern, when the
distribution spans a range of admixture and backcrosses towards both
parental species; bimodal hybridization pattern, when the distribution
is deviated to the two parental or parental-like genotypes, and few
hybrids (F1 and F2 hybrids); and
introgressed hybridization pattern, when the distribution was deviated
to one parental-like genotype.
Figure 4. Heterozygosity
violin plot by population. A ) I. elegans without
hybrids, B ) I. elegans with hybrids, C )I. graellsii with hybrids, D ) I. graellsiiwithout hybrids. Violin width represents the relative frequency of SNPs
at each observed heterozygosity value, i.e., wider violin areas show
higher number of SNPs at that heterozygosity. The line and the circle at
each violin represents the median and the average HO,
while the triangle points at the average HE. Finally,
the value above each violin shows the percentages of SNPs that showed
statistical differences between HO and
HE (p < 0.05) to the total number of
non-missing-data SNPs.