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Additivity of ISSR markers in natural hybrids of related forest species Bromus benekenii and B. ramosus (Poaceae)

100%

Sutkowska A. , Pasierbinski A. , Baba W. , Warzecha T. , Mitka J.

nr 1

The co-occurrence of hybrids and parental species in similar ecological niches poses a question on the role of traits additivity and overdispersion (emergence of new traits) in microevolutionary processes. We analysed genetic polymorphism of Bromus benekenii, B. ramosus and the spontaneous hybrid B. benekenii × B. ramosus in sympatric and allopatric parts of the species distribution in Europe, based on non-coding regions of the taxon genomes (ISSR genetic fingerprinting). We tested 68 individuals in 7 populations, including a hybrid population in N France. Altogether 233 polymorphic ISSR bands (loci) were obtained. We found that the parent species were genetically distinct and the hybrids had an additive pattern of ISSR bands found in the putative parental species (NMDS, STRUCTURE); however, there was evidence of introgression towards B. ramosus (NEWHYBRIDS, UPGMA classifications, Nei's D genetic distance). Bromus benekenii had 72, B. ramosus 21 and the hybrids 9 private bands (genetic overdispersion), probably resulting from the rearranged genomes. Based on its low genetic divergence index DW, the hybrid population seems to be at a young age. We argue that in the face of anthropogenic landscape transformations favouring secondary contacts, the hybrids may competitively replace the parental species in sympatric areas.

Stream habitat conditions and fish fauna within the occurrence range of Walecki barbel, Barbus cyclolepis waleckii Rolik, 1970 [Teleostei: Cyprinidae] in Polish part of the Carpathian Mts

58%

Amirowicz A. , Kukula K.

nr 4

Existing data on Wałecki barbel are very scarce and need a complement to the quantitative description of its habitat conditions. This fish is a subspecies of the Pontic species B. cyclolepis Heckel which occurs in some coastal rivers of the Black Sea or, as evidenced by some results of studies on mitochondrial DNA, it is a hybrid originating from natural crossing between the common barbel Barbus barbus (L.) and spotted barbel B. carpathicus Kotlík, Tsigenopoulos, Ráb et Berrebi. Until now the Wałecki barbel was reported from 26 sites in the river basins of the Upper Vistula and the Dniester in SE Poland (49°09’–49°49’N, 21°28’–22°50’E, altitude 200–590 m). Seventeen of these sites were studied in autumn 2002 and summer 2003 to collect data on habitat parameters of stream channels. The main characteristics of their morphology (i.e. length, width, depth, and gradient) were calculated on the basis of a set of field measurements. Current velocity was measured using float method. The composition of bottom substratum was estimated using a simple scale based on Wentworth scale. Additionally, two biotic characters were included, i.e. the occurrence of macroscopic aquatic vegetation and the species composition of fish community. According to the obtained results the habitat conditions appropriate for Wałecki barbel may be defined as follows: 1) The stream should be medium-sized, at least 10-m or better 20-m wide. 2) The mean channel depth should exceed 20 cm, while the maximum depth should be greater than 50 cm. The channel morphology with the zone of medium depth (i.e. that extending over the half of bottom) in range between at least 15 and 40 cm seems to be favorable. 3) The mean stream velocity of 0.30 m s⁻¹ or more is desired. It seems that the zone of fast current (0.50– 1.00 m s⁻¹) sharing a considerable portion of the channel is an important habitat feature. 4) Most of the bottom area should be covered by mediumsized particles (2–200 mm) with the mode within range of fine pebbles (20–50 mm). 5) In general, the stream should be rather oligotrophic than eutrophic with poorly developed macroscopic algae and the absence of vascular plants, and with flow fluctuations periodically disturbing structure of bottom substratum. 6) The abundant occurrence of spotted barbel, especially within lower part of its distribution area and in the zone of its co-occurrence with common barbel may be regarded as a good indicator of the stream habitat appropriate for Wałecki barbel. 7) Other frequent and abundant species accompanying Wałecki barbel are minnow Phoxinus phoxinus (L.), stone loach Barbatula barbatula (L.), chub Leuciscus cephalus (L.) and schneider Alburnoides bipunctatus (Bloch).