• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. Aug 1, 1993; 90(15): 7079–7083.

Habitat-dependent hybrid parentage and differential introgression between neighboringly sympatric Daphnia species.


Allozyme, morphological, and PCR-generated mtDNA markers were used to analyze hybrid parentage and introgression between the neighboringly sympatric crustaceans Daphnia galeata mendotae and Daphnia rosea. mtDNA analysis of D. galeata mendotae from 15 lakes and of D. rosea from 8 lakes revealed species-specific fragment patterns resulting from TaqI and RsaI digestion. No individuals of one parent species possessed the typical mtDNA of the other parent species, suggesting that mtDNA introgression is rare or nonexistent. Hybrids from 18 lakes possessed either the mtDNA patterns of D. rosea or of D. galeata mendotae, indicating that reciprocal hybridization occurs. The mtDNA genome of the dominant parent species in a lake was overrepresented in the hybrids, suggesting that hybridization most often involves females of the common species and males of the rare species. Such a pattern is consistent with the differing importance of density to the environmental induction of males and sexual eggs in Daphnia. For the assessment of nuclear gene flow, eight sympatric populations of each parental taxon and seven allopatric populations of D. galeata were analyzed for allozyme variation at nine polymorphic loci. Our results provided evidence for asymmetric interspecific gene flow involving alleles at six loci that are unlikely to be convergent or symplesiomorphic. This reticulate evolution accounted for much of the genetic divergence between European and North American populations of D. galeata.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.1M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Avise JC, Saunders NC. Hybridization and introgression among species of sunfish (Lepomis): analysis by mitochondrial DNA and allozyme markers. Genetics. 1984 Sep;108(1):237–255. [PMC free article] [PubMed]
  • Takahata N, Slatkin M. Mitochondrial gene flow. Proc Natl Acad Sci U S A. 1984 Mar;81(6):1764–1767. [PMC free article] [PubMed]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...