Aphanius almiriensis, a new species of toothcarp from Greece (Teleostei: Cyprinodontidae)

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Patterns of variability at the major histocompatibility class I and class II loci in populations of the endangered cyprinid Ladigesocypris ghigii

The patterns of MHC diversity were studied at UAA and DAB1 loci and the two domains involved in the recognition of antigenic peptides (alpha 2 and beta 1, respectively) in eight Ladigesocypris ghigii populations inhabiting streams and a concrete reservoir, in order to understand the significance of these genes in bottlenecked populations of an endemic species and develop conservation rationale. In agreement with previous study employing RAPD and mtDNA markers (Mamuris et al., Freshw Biol 50:1441-1453, 2005), both loci exhibited a very low level of polymorphism with only two and four alleles detected for UAA and DAB1, respectively. The functional MHC diversity was even lower since UAA alleles were distinguished by a single synonymous substitution. The type of habitat did not affect the level of polymorphism. Our data suggest that DAB1 polymorphism might be the outcome of the positive selection, imposed by the temporal and spatial variation of pathogen load, and the genetic drift as a result of successive habitat shrinkage and deterioration by water abstraction year after year. The populations studied were significantly less diverged at MHC loci than expected based on nuclear and mtDNA markers, suggesting that common parasites might act as causative factors to homogenize selection. Sufficient epidemiological data are required for the interpretation of the results and decision-making on suitable conservation actions

Genetic variation in populations of the endangered fish Ladigesocypris ghigii and its implications for conservation

1. The genetic variation of the endangered freshwater fish Ladigesocypris ghigii, endemic to the island of Rhodes (Greece), was investigated for nine populations, originating from seven different stream systems and a reservoir, both at the mtDNA and nuclear level, in order to suggest conservation actions. 2. Both restriction fragment length polymorphism analysis of five segments of mitochondrial DNA (ND-5/6, COI and 12S-16S rRNA) amplified by polymerase chain reaction, and random amplified polymorphic DNA analysis, revealed extremely low levels of intra-population polymorphism. It is highly likely that the low intra-population variability is the result of successive bottleneck events evident in shrinkage and expansion of the populations year after year, which may have led to a complete loss of several genotypes and haplotypes, and an increased degree of inbreeding. 3. Inter-population genetic structuring was high, with fixation of haplotypes within six of the nine populations and fixation of alleles within populations originating from different waterbodies. It is probable that all haplotypes and/or alleles found were initially represented in all populations. However, because of the long time of isolation coupled with successive bottleneck and subsequent genetic drift, common mtDNA haplotypes and alleles among the populations may have become rare or extinct through stochastic lineage loss. 4. Although nucleotide divergence among haplotypes was very shallow, half of the haplotypes recorded (three of six), resulted from nucleotide changes on the 12S-16S rRNA segments, which are the most conserved part of the mitochondrial genome. This fact may indicate that the observed genetic variation did not necessarily result only from the retention of ancestral polymorphism, but may have arisen through mutation and complete lineage sorting over a relatively small number of generations, once the populations had become isolated from one another. 5. Our data suggest that two of the L. ghigii populations may be on independent evolutionary trajectories. Considering that each population appears so far well adapted within each site, all populations should be managed and conserved separately

The spawning behaviour of the endangered freshwater fish Ladigesocypris ghigii (Gianferrari, 1927)

peer reviewedLadigesocypris ghigii (Gianferrari, 1927), commonly called gizani, is an endangered freshwater fish endemic to the Greek island of Rhodes. The spawning behaviour of gizani was studied in aquaria, to develop an artificial breeding technique for this endangered species. Spawning in captivity was recorded over 41 spawning days between 15 February and 14 July 2001, under constant temperature (18 or 21 degrees C) and photoperiod 14L/10D. The number of spawning acts in a day was 82 +/- 28. No aggressiveness and no territoriality were developed. The mating system of the fish was polygamous, with females spawning more than once. In captivity, eggs are laid either on aquatic plants or on gravel, while in nature fish spawn mainly on algae and plants. The latter suggests that, as far as breeding substrate is concerned, gizani is an opportunistic species using different substrates when necessary