The genetic differentiation and the phylogenetic relationships of eight Atherina boyeri Greek populations have been investigated at the mtDNA level. The populations studied are from two different lakes, a lagoon, the interface zone between the lagoon and the sea, and four marine sites. RFLP analysis of three mtDNA segments (12s rRNA, 16s rRNA and D-loop) amplified by PCR was used. Six, seven and eight restriction enzymes were found to have at least one recognition site at 12s rRNA, 16s rRNA and D-loop respectively. Twenty-one different haplotypes were detected among the populations studied. Several restriction patterns were revealed. These patterns can be used for the discrimi-

We used the denaturing gradient gel electrophoresis (DGGE) method to define mutations in the promoter region, the 18 exons, and their flanking intronic sequences of the low-density lipoprotein (LDL) receptor gene LDLR, causing familial hypercholesterolemia (FH) phenotype in 100 German and in 100 Greek hypercholesterolemic individuals. In addition, we tested all patients for the presence of mutations in codons 3456-3553 of the gene encoding apolipoprotein B-100 (APOB). Twenty-six aberrant DGGE patterns were identified and subsequently directly sequenced. In LDLR, two novel missense mutations (c.1957G>T/p.V653F, c.647 G>A/p.C216Y) and one novel homozygous base substitution c.1-156 C>T in the repeat 2 of the promoter region were identified among German FH patients; one novel splice site c.1060+10C>G was identified among Greek FH patients. One of the German FH patients was a carrier for the mutations c.1171G>A/p.A391T and p.V653F, and two of the Greek FH patients were compound heterozygotes for the mutations c.1150C>T/p.Q384X and c.1158C>G/p.D386E. Two German FH patients carried the mutation p.R3500Q within APOB. Comparing the mutations within the LDLR gene of the two European FH populations, the German population seems to be more heterogeneous than the Greek cohort. Further studies in progress are trying to elucidate the responsiveness to drug therapy in association with LDLR genotype and the nutritional habits of the two FH populations.

fading gradually to silver or white in the abdomen; a dark single wide stripe on each side of the body. Caudal peduncle relatively thin; pelvic fins narrow and relatively long; the mouth is terminal. The first rays of the dorsal and anal fins are relatively short reaching to the half of each second ray. Scales tiny cycloid, thin and deeply inserted in the skin; lateral line is incomplete, extends maximally up to the height of the ventral fins. Vertebrae 31, D III, 6-7, P I, 14-15, A III, 6-7, V II, 7, principal caudal rays 22 (19-23), pored LL 15-22, pharyngeal teeth 5-5. Gillrakers 11 rather dense, long and thin. P. epiroticus is short-lived, longevity is about 2-3 years, with rapid growth during the first year of life, attaining 5-6 cm TL. Maximum size 10 cm TL, rarely exceeding 7 cm (Prassa et al. 2003). Distribution: P. epiroticus is endemic in Lake Pamvotis of Epirus, NW Greece (Stephanidis 1974). Abundance: Until the end of the 1980s, P. epiroticus was very abundant but heavily exploited. It is now considered critically endangered. Habitat and ecology: P. epiroticus is a schooling fish often found in association with spring outflows and adjacent to aquatic macrophytes. They feed on a wide range of small aquatic invertebrates especially crustaceans, algae, larvae of winged insects, small insects and worms. Reproduction: Sexual maturity is reached during the first year of life. Spawning occurs from middle of March to end of April. Spawning sites are near springs and inflows of water. Eggs are yellowish, adhesive and deposited mainly on aquatic plants. Threats: P. epiroticus is nearly extinct due to the cumulative impacts of habitat degradation and fragmentation by ecologically unsustainable agricultural development. This includes excessive water abstraction, eutrophication, changes in the physicochemical parameters of the water, water level fluctuations during spring and the absence of submerged macrophytes (due to the increased turbidity and alien fish species (e.g. Ctenopharyngodon idellus) nutritional preferences). Its current status may also be attributed to the presence of indigenous predatory species such Silurus aristotelis but in particular European eels (Anguilla anguilla). The numbers of eels have increased recently due to management of the population by local fishermen. Alien cyprinid species have also been introduced (Economidis 1991) which compete with P. epiroticus for feeding and/or spawning grounds. Furthermore, the species is subject to predation from water snakes and several aquatic birds, especially great cormorants (Phalacrocorax carbo) which have increased in numbers during the last decade (Perdikaris et al. 2003). The above threats in combination with the intensive fishing pressure, practiced by local fishermen, have significantly decreased the P. epiroticus population. Conservation action: P. epiroticus is included in the Annex II of the European Council Directive 92/43 ''The Conservation of Natural Habitats, Wildlife and Flora''. Conservation recommendation: Provisions should be made...

In a patient with familial hypercholesterolemia (FH), we have identified a new mutation (-45delT) in repeat 3 of the low-density lipoprotein receptor (LDLR) gene promoter. Analysis of a neutral polymorphism in the LDLR mRNA from the patient's white blood cells showed that the expression of one allele was significantly reduced, and cells have only 24% of LDLR activity by binding and uptake of DiI-LDL. Transient transfection studies using a luciferase gene reporter revealed that the -45delT mutation considerably reduces the transcriptional activity of the LDLR promoter and strongly suggest that the mutation is the cause of the FH phenotype.