Search results for "DNA"

Elucidating geological and biological processes underlying the diversification of Sulawesi tarsiers.

2009

Because of their exceptionally long independent evolution, a range diminution of their Eocene relatives, and a remarkable subsequent diversification in Southeast Asia, tarsiers are of particular importance to evolutionary primatologists. Little is known, however, on the processes shaping the radiation of these small enigmatic primates—especially on the Indonesian island of Sulawesi, their center of endemism. Geological reconstructions and progress in applying DNA sequence information to divergence dating now provide us with the tools and background to comprehend tarsier dispersal. Here, we describe effects of plate-tectonic movements, Pleistocene sea level changes, and hybridization on the…

Phylogeography of a Palaearctic sedentary passerine, the willow tit (Parus montanus)

2001

We analysed variation of the mitochondrial control region from willow tits through its Palaearctic distribution range. Although we found high amount of genetic variation (π=1.114%), there was almost no differentiation between subspecies or geographical localities. This may be because of a combination of several ecological and genetic factors, including a relatively homogenic habitat through the distribution range, lack of geographical barriers, high gene flow and a large long-term effective population size. On the contrary, in the songar tit, which is sometimes considered to be conspecific with the willow tit, the mitochondrial lineages seem to correlate with the geographical locality and a…

Environmental features of deep-sea habitats linked to the genetic population structure of a crustacean species in the Mediterranean Sea

2009

The deep-sea habitat, from 200 to 2000 m depth, has long been thought as an ecosystem where biotic and abiotic factors vary very little and consequently species are not disturbed by processes and phenomena which could promote fast evolutionary mechanisms. Unfortunately, biological information relating to deep water is limited, especially regarding the population genetics of species inhabiting the Mediterranean Sea, and general patterns cannot be inferred. In this study we report data on the population genetic structure of Aristeus antennatus, a deep-sea decapod crustacean species which has been widely studied due to its important economic value. We surveyed and examined the variation in a 3…

Use of the molecular markers as a tools in fishes stock assessment.

2010

Isolamento per distanza in popolazioni mediterranee di Parapenaeus longirostris (Crustacea: Decapoda).

2011

Italian Peninsula preserves an evolutionary lineage of the fat dormouse Glis glis L. (Rodentia: Gliridae)

2011

Mitochondrial DNA deletion and male infertility

2009

Abstract The term “male infertility” does not constitute a defined clinical syndrome, but rather, a collection of different conditions exhibiting a variety of aetiologies and varying diagnosis. In men, oligozoospermia, asthenozoospermia, teratozoospermia and azoospermia are the main causes of infertility. The present research is aimed to investigate if mtDNA deletions can cause sperm defects in idiopathic astenozoospermic patients with different sperm motility and sperm concentration. The incidence of deletions in mtDNA (mtDNA) was co-related with diagnostic categorization of male infertility when 6.6kb out of the 16.6kb of the mitochondrial genome was amplified from whole sperm samples, f…

Prediction of harmful variants on mitochondrial genes : Test of habitat-dependent and demographic effects in a euryhaline fish

2017

Both effective population size and life history may influence the efficacy of purifying selection, but it remains unclear if the environment affects the accumulation of weakly deleterious nonsynonymous polymorphisms. We hypothesize that the reduced energetic cost of osmoregulation in brackish water habitat may cause relaxation of selective constraints at mitochondrial oxidative phosphorylation (OXPHOS) genes. To test this hypothesis, we analyzed 57 complete mitochondrial genomes of Pungitius pungitius collected from brackish and freshwater habitats. Based on inter- and intraspecific comparisons, we estimated that 84% and 68% of the nonsynonymous polymorphisms in the freshwater and brackish …

Signals of demographic expansion in Drosophila virilis

2008

Background. The pattern of genetic variation within and among populations of a species is strongly affected by its phylogeographic history. Analyses based on putatively neutral markers provide data from which past events, such as population expansions and colonizations, can be inferred. Drosophila virilis is a cosmopolitan species belonging to the virilis group, where divergence times between different phylads go back to the early Miocene. We analysed mitochondrial DNA sequence variation among 35 Drosophila virilis strains covering the species' range in order to detect demographic events that could be used to understand the present characteristics of the species, as well as its differences …

Prime indicazioni sulle biocenosi associate alle mummie delle Catacombe dei Cappuccini di Palermo

2009

La fama del convento, costruito dai Cappuccini di Palermo nel 1533, è dovuta in gran parte alle famose "Catacombe". L’origine delle catacombe si fa risalire al 1599 circa, quando i frati, sfruttando una preesistente cavità naturale al di sotto dell’altare maggiore della chiesa, trasferirono le salme di 40 frati precedentemente sepolti presso il lato meridionale della chiesa stessa. I frati iniziarono ad ampliare le catacombe, scavando nel sottosuolo, in relazione al crescente numero di nuove salme che nel tempo si conservavano. Allo stato attuale le catacombe sono una sorta di cimitero sotterraneo, in uso nel XVII secolo, costituito da lunghe gallerie scavate nel tufo per un’estensione di c…