Diga-se de passagem que Amabis e Martho deixaram de usar esta fraude em seu livro-texto de Biologia do ensino médio, mas não dizem por que o fizeram em anos anteriores.
É, estão resgatando a dignidade e salvando a cara de Kettlewell...+++++
Selection and gene flow on a diminishing cline of melanic peppered moths
1. Ilik J. Saccheri,†,
2. François Rousset‡,
3. Phillip C. Watts*,
4. Paul M. Brakefield§,¶, and
5. Laurence M. Cook‖
+Author Affiliations
1. *School of Biological Sciences, Biosciences Building, Crown Street, University of Liverpool, Liverpool L69 7ZB, United Kingdom;
2. ‡Institut des Sciences de l'Evolution, Université Montpellier 2, 34095 Montpellier, France;
3. §Institute of Biology, Leiden University, P.O. Box 9516, 2300 RA Leiden, The Netherlands;
4. ¶Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom; and
5. ‖Manchester Museum, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
1. Edited by John C. Avise, University of California, Irvine, CA, and approved August 20, 2008 (received for review April 28, 2008)
Abstract
Historical datasets documenting changes to gene frequency clines are extremely rare but provide a powerful means of assessing the strength and relative roles of natural selection and gene flow. In 19th century Britain, blackening of the environment by the coal-fired manufacturing industry gave rise to a steep cline in the frequency of the black (carbonaria) morph of the peppered moth (Biston betularia) across northwest England and north Wales. The carbonaria morph has declined across the region following 1960s legislation to improve air quality, but the cline had not been comprehensively described since the early 1970s. We have quantified changes to the cline as of 2002, equivalent to an interval of 30 generations, and find that a cline still exists but that it is much shallower and shifted eastward. Joint estimation of the dominant fitness cost of carbonaria and dispersal parameters consistent with the observed cline change indicate that selection against carbonaria is very strong across the landscape (s ≈ 0.2), and that dispersal is much greater than previously assumed. The high dispersal estimate is further supported by the weak pattern of genetic isolation by distance at microsatellite loci, and it implies that in addition to adult dispersal, wind-dispersed first instar larvae also contribute to lifetime dispersal. The historical perspective afforded by this study of cline reversal provides new insight into the factors contributing to gene frequency change in this species, and it serves to illustrate that, even under conditions of high dispersal and strong reverse selection acting against it, complete erosion of an established cline requires many generations.
Biston betularia - industrial melanism - cline change
†To whom correspondence should be addressed. E-mail: saccheri@liv.ac.uk
Author contributions: I.J.S., P.M.B., and L.M.C. designed research; I.J.S. and P.C.W. performed research; I.J.S., F.R., P.C.W., and L.M.C. analyzed data; and I.J.S., F.R., P.C.W., and L.M.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
© 2008 by The National Academy of Sciences of the USA.
PDF gratuito aqui no PNAS.
