TY - JOUR
T1 - Allopatric genetic origins for sympatric host-plant shifts and race formation in Rhagoletis
AU - Feder, Jeffrey L.
AU - Berlocher, Stewart H.
AU - Roethele, Joseph B.
AU - Dambroski, Hattie
AU - Smith, James J.
AU - Perry, William L.
AU - Gavrilovic, Vesna
AU - Filchak, Kenneth E.
AU - Rull, Juan
AU - Aluja, Martin
PY - 2003/9/2
Y1 - 2003/9/2
N2 - Tephritid fruit flies belonging to the Rhagoletis pomonella sibling species complex are controversial because they have been proposed to diverge in sympatry (in the absence of geographic isolation) by shifting and adapting to new host plants. Here, we report evidence suggesting a surprising source of genetic variation contributing to sympatric host shifts for these flies. From DNA sequence data for three nuclear loci and mtDNA, we infer that an ancestral, hawthorn-infesting R. pomonella population became geographically subdivided into Mexican and North American isolates ≈1.57 million years ago. Episodes of gene flow from Mexico subsequently infused the North American population with inversion polymorphism affecting key diapause traits, forming adaptive clines. Sometime later (perhaps ±1 million years), diapause variation in the latitudinal clines appears to have aided North American flies in adapting to a variety of plants with differing fruiting times, helping to spawn several new taxa. Thus, important raw genetic material facilitating the adaptive radiation of R. pomonella originated in a different time and place than the proximate ecological host shifts triggering sympatric divergence.
AB - Tephritid fruit flies belonging to the Rhagoletis pomonella sibling species complex are controversial because they have been proposed to diverge in sympatry (in the absence of geographic isolation) by shifting and adapting to new host plants. Here, we report evidence suggesting a surprising source of genetic variation contributing to sympatric host shifts for these flies. From DNA sequence data for three nuclear loci and mtDNA, we infer that an ancestral, hawthorn-infesting R. pomonella population became geographically subdivided into Mexican and North American isolates ≈1.57 million years ago. Episodes of gene flow from Mexico subsequently infused the North American population with inversion polymorphism affecting key diapause traits, forming adaptive clines. Sometime later (perhaps ±1 million years), diapause variation in the latitudinal clines appears to have aided North American flies in adapting to a variety of plants with differing fruiting times, helping to spawn several new taxa. Thus, important raw genetic material facilitating the adaptive radiation of R. pomonella originated in a different time and place than the proximate ecological host shifts triggering sympatric divergence.
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U2 - 10.1073/pnas.1730757100
DO - 10.1073/pnas.1730757100
M3 - Article
C2 - 12928500
AN - SCOPUS:0041836288
SN - 0027-8424
VL - 100
SP - 10314
EP - 10319
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 18
ER -