Distortion of symmetrical introgression in a hybrid zone: evidence for locus-specific selection and uni-directional range expansion.

The fate of species integrity upon natural hybridization depends on the interaction between selection and dispersal. The relative significance of these processes may be studied in the initial phase of contact before selection and gene flow reach equilibrium. Here we study a hybrid zone of two salamander species, Lyciasalamandra antalyana and Lyciasalamandra billae, at the initial phase of hybridization. We quantify the degree and mode of introgression using nuclear and mtDNA markers. The hybrid zone can be characterized as an abrupt transition zone, the central hybrid zone being only c. 400 m, but introgressed genes were traced up to 3 km. Introgression was traced in both sexes but gene flow may be slightly male-biased. Indirect evidence suggests that hybrid males are less viable than females. Introgression occurred at two levels: (1) locus-specific selection led to different allelic introgression patterns independent of species, while (2) asymmetrical species-level introgression occurred predominately from L. antalyana to L. billae due to range expansion of the former. This indicates that foreign genes can be incorporated into novel genomic environments, which in turn may contribute to the great diversity of morphological variants in Lyciasalamandra.

Within-subject biological variation of reticulocytes and reticulocyte-derived parameters.

Automation of reticulocyte counting has decreased the analytical imprecision of this parameter. This has made it possible to use the number of reticulocytes and its derived parameters (reticulocyte maturity and reticulocyte cell indices) in new diagnostic and monitoring situations. For rational use of these parameters, it is important to have knowledge of their biological variability. The biological variability of reticulocytes and its derived parameters was studied in 13 healthy people during a period of 7 wk on 2 different instruments. The within-subject coefficient of variation for the reticulocyte count was about 11%, for the mean reticulocyte volume, mean reticulocyte haemoglobin content and mean reticulocyte haemoglobin concentration it was between 1 and 2%, whereas the coefficient of variations for the subpopulations of reticulocytes with different maturity varied depending on the method used for the measurements. The critical difference, that is the change in a result making it significantly different from the previous result, was about 35% for the reticulocyte count and 5-8% for the reticulocyte cell indices, making these indices excellent to follow changes in erythropoiesis. With a possible exception for the mean reticulocyte volume, the within-subject variation was small compared to the between-subject variation.