You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Origin of Thermal Adaptations in Northern Versus Southern Populations of a Unisexual Hybrid Fish
Arthur J. Bulger and R. Jack Schultz
Vol. 36, No. 5 (Sep., 1982), pp. 1041-1050
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2408081
Page Count: 10
You can always find the topics here!Topics: Genomes, Heat stress disorders, Hybridity, Species, Fish, Survival rates, Evolution, Biological adaptation, Heterosis, Cold tolerance
Were these topics helpful?See somethings inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Hemiclones of the unisexual fish Poeciliopsis monacha-occidentalis are not better adapted to cold temperatures in the northern part of their range than in the southern part of their range, nor is there conclusive evidence that they are coadapted to local populations of the sexual host species, P occidentalis. Response of the introgressed monacha genome to thermal stress is not clinal, whether the maternal genome is combined with a paternal genome of P. occidentalis or of P lucida; in fact, the differences in response among populations from the five river systems tested were of the same magnitude as from among hemiclones within the Rio Mayo, the southernmost river and the apparent site of origin of P monacha-occidentalis. Although the resistance to cold stress exhibited by P. monacha-occidentalis may play a role in its survival in the north, and heterosis for resistance to heat stress may contribute to its success in the south, these traits more likely derive from the original hybrid genotypes than from adaptive changes subsequent to their hybrid origin. Thus, it remains to be demonstrated that unisexual Poeciliopsis in the absence of a mechanism for recombination, have the capacity to evolve.
Evolution © 1982 Society for the Study of Evolution