Data from: Phylogenomic analyses confirm a novel invasive North American Corbicula (Bivalvia: Cyrenidae) lineage

The genus Corbicula consists of estuarine or freshwater clams native to
temperate/tropical regions of Asia, Africa, and Australia that
collectively encompass both sexual species and clonal (androgenetic)
lineages. The latter have become globally invasive in freshwater systems
and they represent some of the most successful aquatic invasive lineages.
Previous studies have documented four invasive clonal lineages, Forms A,
B, C, and Rlc, with varying known distributions. Form A (R in Europe)
occurs globally, Form B is found solely in North America, mainly the
western United States, Form C (S in Europe) occurs both in European
watersheds and in South America, and Rlc is known from Europe. A putative
fifth invasive morph, Form D, was recently described in the New World from
the Illinois River (Great Lakes watershed), where it occurs in sympatry
with Forms A and B. An initial study showed Form D to be conchologically
distinct: possessing rust-colored rays and white nacre with purple teeth.
However, its genetic distinctiveness using standard molecular markers
(mitochondrial cytochrome c oxidase subunit I and nuclear ribosomal 28S
RNA) was ambiguous. To resolve this issue, we performed a phylogenomic
analysis using 1,699-30,027 nuclear genomic loci collected via the next
generation double digested restriction-site associated DNA sequencing
method. Our results confirmed Form D to be a distinct invasive New World
lineage with a population genomic profile consistent with clonality. A
majority (7/9) of the phylogenomic analyses recovered the four New World
invasive Corbicula lineages (Forms A, B, C, and D) as members of a clonal
clade, sister to the non-clonal Lake Biwa (Japan) endemic, C. sandai. The
age of the clonal clade was estimated at 1.49 million years (my; ± 0.401–
2.955 my) whereas the estimated ages of the four invasive lineage crown
clades ranged from 0.27-0.44 my. We recovered no evidence of nuclear
genomic admixture among the four invasive lineages in our study
populations. In contrast, 2/6 C. sandai individuals displayed partial
nuclear genomic Structure assignments with multiple invasive clonal
lineages. These results provide new insights into the origin and
maintenance of clonality in this complex system.