We assessed variation in mitochondrial DNA (mtDNA) by restriction fragment length polymorphism (RFLP) analysis and in nuclear genes by allozyme analysis among sympatric pairs of limnetic and benthic ecotypes of whitefish (Coregonus) coexisting in three lakes of southern Yukon to address three evolutionary questions regarding their origins. Are sympatric low and high gill-raker count ecotypes ge...

Natural populations of the marine cyanobacterium Prochlorococcus exist as two main ecotypes, inhabiting different layers of the ocean's photic zone. These so-called high light- (HL-) and low light (LL-) adapted ecotypes are both physiologically and genetically distinct. HL strains can be separated into two major clades (HLI and HLII), whereas LL strains are more diverse. Here, we used several m...

The abundance, spatio-temporal distribution, and feeding of larvae were compared from two reproductively isolated dwarf and normal ecotypes of whitefish (Coregonus sp.) to test the hypothesis that larval ecotypes should reduce competition by using different resources. Contrary to a priori expectations, trophic niche partitioning between larval populations was much less pronounced than previousl...

Pearl millet (Pennisetum glaucum (L.) R. Br) is a staple food in many developing countries and constitutes the major source of essential nutrients in semi-arid and arid regions of Africa and India. The knowledge about the nutrient content of autochthonous pearl millet ecotypes is scarce. In this study, biochemical analysis of six Tunisian pearl millet ecotypes has been investigated. Results pro...

Previous research has shown that sequences of 16S rRNA genes and 16S-23S rRNA internal transcribed spacer regions may not have enough genetic resolution to define all ecologically distinct Synechococcus populations (ecotypes) inhabiting alkaline, siliceous hot spring microbial mats. To achieve higher molecular resolution, we studied sequence variation in three protein-encoding loci sampled by P...

Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotype...

BACKGROUND AND AIMS The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the adaptation of Poa bulbosa, ...

Background: Hormones regulate the expression of multiple phenotypic traits. Therefore, divergence in hormone concentrations may lead to evolutionary changes in the coordinated physiological and behavioural traits that comprise an organism’s integrated phenotype. Adults of marine ecotypes of threespine stickleback (Gasterosteus aculeatus) have higher concentrations of the thyroid hormone thyroxi...

The bean (Phaseolus vulgaris L.) is one of the best known of the legumes, and it has a long cultivation tradition in Italy. The territory of “Subappennino Dauno” (southern Italy) is at around 700 m a.s.l. and is predominantly grown with cereals, olive trees and grapevines. Ecotypes of white beans to eat dry (such as cannellini beans) are also grown, which are sought for their palatability, high...