RESUMEN
Dynamics of the telomeric DNA (tDNA) and the phylogeny of the Baikal and Siberian planarians have been studied based on the analysis of the 18S rDNA and beta-actin gene fragments. A relationship between tDNA and the planarians size has been demonstrated. Giant planarians with a minor exception have longer tDNA than little planarians. Phylogenetic affinity between the species that have the stretched tracks of tDNA, big size and similar habitats may indicate possible role of tDNA in the development of the indefinite regenerative capacity of planarians.
Asunto(s)
Actinas/genética , ADN de Helmintos/genética , Filogenia , Planarias/genética , ARN Ribosómico 18S/genética , Telómero , Actinas/clasificación , Animales , Tamaño Corporal/genética , ADN de Helmintos/clasificación , Planarias/clasificación , ARN Ribosómico 18S/clasificación , Regeneración/genética , Siberia , Especificidad de la EspecieRESUMEN
Genome size of Cyclops in cells at early stages of cleavage (up to the 5th division) and in somatic cells were estimated by a static digital Feulgen cytophotometry in order to study the quantitative changes in DNA content during chromatin diminution. Our realization of the cytophotometric method was approbeted on five different digital-imaging systems in blood cells of four vertebrate species. In all cases, we observed a direct correlation of the obtained and known from the literature data on the genome size and a high reproducibility, which allows to use these systems in future work. We also optimized the conditions for DNA hydrolysis of both blood smears, and for two species of Cyclops from the Moscow population, as 30 min in 5 N HCl at 24 degrees C. Here we first revealed chromatin diminution in two endemic Baikal species of Cyclopoida: Acanthocyclops incolotaenia and Diacyclops galbinus estimated the extent ofchromatin diminution in Diacyclops galbinus as 95.5-96.2 %. Cytometric analysis of the third species, Mesocyclops leuckarti, did not reveal obvious chromatin diminution. We also optimized the conditions for DNA hydrolysis of both blood smear preparations, and for two species of copepods from the Moscow population, as 30 min in 5N HCl at 24 degrees C.
Asunto(s)
Copépodos/citología , Copépodos/metabolismo , Citofotometría/métodos , ADN/metabolismo , Genoma/fisiología , Animales , Copépodos/genética , ADN/genética , SiberiaRESUMEN
The length of the telomeric DNA in nine species of planarians inhabiting Lake Baikal and one Siberian species from Baikal rivers was determined using Southern hybridization. According to preliminary estimations, it varied in the range of 25-30 kb (Rimacephalus arecepta, Rimacephalus pulvinar, Sorocelis hepatizon, Sorocelis nigrofasciata, Protocotylus sp., Baikalobia guttata, Bdellocephala baikalensis, Phagocata sibirica) and 50 kb (Baikaloplana valida, Baikalobia copulatrix). It is the first estimation of the values of telomeric region lengths for Baikal free-living flat worms.
Asunto(s)
ADN de Helmintos/genética , Planarias/genética , Telómero/genética , Animales , Agua Dulce , Siberia , Especificidad de la EspecieRESUMEN
Baikalian cyclopoids represent one of the richest endemic faunas of freshwater cyclopoid copepods. The genus Diacyclops Kiefer, 1927 is the most numerous by species number in the lake. In this work, molecular-phylogenetic analysis of 14 species and 1 sub-species from Lake Baikal and its water catchment basin is performed. The regions of mitochondrial cytochrom-oxydase I (COI) and of nuclear small-subunit 18S rRNA were used as evolution markers. In the obtained set of nucleotide sequences of COT gene, an effect of synonymous substitution saturation is revealed. Baikalian representatives of the genus Diacyclops form at phylogenetic schemes by two markers a monophyletic griup, it suggest their origin from a common ancestral form. Preliminary estimate of the age of this group is 20-25 My.
Asunto(s)
Copépodos/genética , Animales , Complejo IV de Transporte de Electrones/genética , Evolución Molecular , Agua Dulce , Genes Mitocondriales , Filogenia , Subunidades de Proteína/genética , ARN Ribosómico 18S/genética , SiberiaRESUMEN
Three new microsatellite loci found for the Baikal omul Coregonus migratorius (Georgi) are described.
Asunto(s)
Salmonidae/genética , Animales , Repeticiones de MicrosatéliteRESUMEN
The fragment of mitochondrial cytochrome b gene from 16 species of Baikalian sculpins belonging to three families--Cottidae, Comephoridae and Abyssocottidae--was amplified by polymerase chain reaction and sequenced. Phylogenetic trees were built from data obtained. Some disconformity were noted between systematical and phylogenetic notions of today and obtained results. For example, branch lengths among some Cottidae species are larger than among any different family species. Moreover, schemes indicate separate position of Limnocottus euristomus from Limnocottus genus species. Phylogenetic trees confirm earlier conclusions, about recent--in geological scales of times--origin of baikalian Cottoidei (2-2.5 Myr).