We studied the recent evolution of the species range of Cyclope neritea, a marine Nassariid gastropod discovered thirty years ago along the French Atlantic and English Channel coasts, at the edge of its previously recognized native range. The particular geographical location of the newly recorded populations made likely a natural range expansion towards North in response to global warming. However, given habitat discontinuities and the low dispersal abilities of C. neritea, we had to consider the alternative hypothesis of a recent introduction related to human-mediated exchanges of cultivated species to explain this sudden range expansion.
By studying mitochondrial and nuclear polymorphisms, we showed a strong phylogeographic structure in the native range of C. neritea, as expected for a direct-developing species. Thanks to this structure, we demonstrated that the appearance of new populations near the range limit of the species was mainly caused by massive and recurrent human-mediated introductions of individuals coming from several highly divergent sources in the native range. Nevertheless, we could not exclude the possibility of a historical presence of cryptic populations (at low density) originating from natural spread that could be now reinforced by the temperature increase in the eastern Atlantic. The recent evolution of the range of C. neritea is thus an example of the synergistic action of both natural and human-mediated processes, acting on long and short time scales.
Keywords: Species range, natural expansion, biological introductions, coastal areas, phylogeography, gene flow, mollusk.
A Brief Biography of Dr. Jun Yu
Dr. Jun Yu is currently a professor and Associate Director of Beijing Genomics Institute, Chinese Academy of Sciences (CAS). He has joint appointments and supervises graduate students at the Institute of Computer Sciences (CAS), Zhejiang University, and Chinese Agricultural University. Dr. Yu obtained his B.S. degree in biochemistry from Jilin University in 1983 and Ph.D. degree in biomedical sciences from New York University Medical School in 1990. He had worked as a Research Assistant Professor at NYU since 1990 until he joined University of Washington Genome Center in 1993. Dr. Yu's primary research interests include genome biology and bioinformatics. He has led many major genome projects in China, including the Human Genome Project (the Chinese effort; known as the 1% Genome Project), the Superhybrid Rice Genome Project, the Silkworm Genome Project, and the Chicken Genome Diversity Project, which all resulted in high-impact publications in major international journals, including Science, Nature, and PLoS Biology. He has published over 100 scientific papers and a few dozens of books and book chapters. Dr. Yu has won numerous academic awards, including the Award for Outstanding Science and Technology Achievements (Group, 2003, Chinese Academy of Sciences), Scientific Leader of the Year, 2002 (The first "SA50" Award by the journal Scientific American), "Qiushi" Award for Scientific Achievement (Group, 2002, QiuShi Science and Technology Foundation, Hong Kong), 100-Talent Plan (Chinese Academy of Sciences, 2002-2005), Outstanding Young Investigator Award (B Class, the Natural Science Foundation, 1999-2002), American Foundation for Urological Diseases Ph.D. Research Scholar (1991-1993), China-US Biology Examination and Application (CUSBEA,1983).