Correspondence: M. Morgan-Richards. Fax: +64 3-479 7584; E-mail:email@example.com
Genetic structure and differentiation of Plantago major reveals a pair of sympatric sister species
Article first published online: 4 JAN 2002
Volume 8, Issue 6, pages 1027–1036, June 1999
How to Cite
Morgan-Richards, M. and Wolff, K. (1999), Genetic structure and differentiation of Plantago major reveals a pair of sympatric sister species. Molecular Ecology, 8: 1027–1036. doi: 10.1046/j.1365-294x.1999.00665.x
Present addresses:†Department of Zoology, Otago University, PO Box 56, Dunedin, New Zealand;‡University of Newcastle, Department of Agricultural and Environmental Sciences, Newcastle upon Tyne NE1 7RU, UK.
- Issue published online: 4 JAN 2002
- Article first published online: 4 JAN 2002
- Received 29 October 1998; revision received 4 February 1999;accepted 14 February 1999
- genetic diversity;
- mating systems;
- population structure;
Seeds of the widespread weed Plantago major were collected from 10 European countries, as well as Trinidad and North America. The seed collections were from populations of two taxa which are ecologically rather than geographically separated and formally recognized as the subspecies Plantago major ssp. major and P.m. ssp. intermedia (also called P.m. ssp. pleiosperma). Eight polymorphic allozyme loci and 73 random-primed DNA fragments were scored, as well as 11 morphological characters. Complete concordance between morphological traits and genetic data provides evidence that these two taxa, although very similar, are distinct species. They are both widespread, they are broadly sympatric and capable of interbreeding. However, slight morphological and ecological differences coincide with genetic clustering of populations from widely separated locations. In addition, P. major and P. intermedia differ in their population structure: P. intermedia has greater genetic diversity among populations and less genetic variance within populations than P. major. We suggest that differences between the two species in their levels of selfing may explain the distinctive genetic structure of each species. We hypothesize a link between selfing rate and lifespan of the two taxa. P. major is characterized by lower genetic variation among populations, a higher rate of outcrossing, longer lifespan and production of fewer seeds per seed capsule. P. intermedia is more highly structured with much differentiation among populations, a higher rate of inbreeding and it often grows as an annual.