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FIG. 2. — Stachorutes najtae n in Stachorutes najtae n. sp., a new psammophile species of Collembola from Italy (Neanuridae, Pseudachorutinae)
No full textFIG. 2. — Stachorutes najtae n. sp.: A, B, dorsal and ventral chaetotaxy of Ant. III-IV; C, chaetotaxy of Ant. I-II; D-F, chaetotaxy of femora and tibiotarsi of leg I, II and III respectively; G, chaetotaxy of furca and retinaculum; H, male genital opening; I, female genital opening. Scale bars: A-F, 10 µm; G-I, 25 µm.Published as part of Fanciulli, Pietro Paolo, Dallai, Romano, Frati, Francesco & Carapelli, Antonio, 2017, Stachorutes najtae n. sp., a new psammophile species of Collembola from Italy (Neanuridae, Pseudachorutinae), pp. 31-36 in Zoosystema 39 (1) on page 34, DOI: 10.5252/z2017n1a4, http://zenodo.org/record/457849
Animal inference on human mitochondrial diseases
No full textSeveral pathological mutations in the human mitochondrial genome have been characterized based on medical, genetic and biochemical evidence. The observation that the structure and core functions of the mitochondrial genome are conserved from animals to man suggests that the analysis of animal variation may be informative to further characterize, and possibly predict, human pathological variants. We studied the distribution of sequence site-wise diversity and structural heterogeneity (based on several scales of hydrophobicity and supercomplex classification of mitochondrial genes) at different taxonomic levels in ∼15,000 human and animal genomes. We found that human pathological mutations tend to lay in regions of low diversity and that states that are pathological in humans appear to be extremely rare in animals, with two noticeable exceptions (T10663C and C14568T). Focusing on hydrophobicity, as possibly the most general site-wise functional parameter of a protein, we deploy the observed range of hydrophobicity in mammals as a proxy for the range of permissible states compatible with an efficient functioning of the mitochondrial machinery. We show that, while non pathological human variants tend to fall within the hypothesized range, pathological mutations generally fall outside this range. We further analyzed this distribution quantitatively to show that the estimated probability of observed states can indeed be used to predict the pathogenicity of a mutation in humans. This study provides a proof of principle that animal data can indeed be informative to predict the pathogenicity of a human mutation alongside, or in the absence of, additional evidence
Post-zygotic sex-determination in Symphypleonan Collembola: cytological implications and evolutionary significance.
No full textIsolation of novel microsatellite loci in Orchesella villosa (Arthropoda, Collembola)
No full textAn experimental procedure using biotin-labelled probes and streptavidin-bound magnetic beads (FIASCO) was used to produce a microsatellite-enriched library for the collembolan Orchesella villosa. PCR primers were successfully constructed for seven loci containing, respectively, five pure, one interrupted, and one compound dinucleotide microsatellite repeats. As a preliminary test of their variability, we investigated 15 individuals from 5 locations inside a dismissed mining area in southern Tuscany. All microsatellite loci showed high levels of polymorphism. The mean number of different alleles at each locus across populations was 10.1 and observed heterozygosity per locus was 0.13–0.86. Only 2 out of the 7 loci appeared to be in Hardy–Weinberg equilibrium. The potential application of these loci to test the effects of environmental contamination on the genetic structure of exposed populations is discussed
Secondary structure and sequence variation of the 28S rRNA gene in the Neanuridae, and its utility as a phylogenetic marker
No full textA fragment of the 28SrRNA encompassing the divergent domains D1-D5 was sequenced in 14 species of Collembola Neanuridae, 12 of which belong to the subfamily Neanurinae. A slight length variation across taxa was found in the D2, D3 and D5 divergent domains, the core regions being very conserved in length and sequence. Nucleotide composition was slightly biased towards As and Ts (55.6%), with the bias being more evident in the nucleotides not involved in pairing with complementary sequences. A+T bias was higher in the divergent domains than in the core regions. The number of variable sites was high in the divergent domains, and positively correlated to their length, with the D2 domain being the longest and the most variable one. Phylogenetic analysis strongly suggested monophyly of the Neanurinae and less strongly of the Neanurini. It also suggested polyphyly of the genera Neanura and Deutonura. Some relationships are in contrast with morphological evidences, but are in agreement with molecular data from the mitochondrial COII gene
Investigation on the taxonomic status of Steganacarus magnus and Steganacarus anomalus (Acari: Oribatida) using mitochondrial DNA sequences.
No full textTo test the previously suggested synonymization of S. anomalus with the older S. magnus, a fragment of the mitochondrial COI gene was amplified via the polymerase chain reaction and sequenced. The sequence variation was examined in a total of 327 base pairs for four steganacarid mite populations, two of which belong to S. anomalus, one to S. magnus and one to S. hirsutus. The sequence variation suggests that S. magnus and S. anomalus are not distinct species and that the population from Fioreta (Siena) is more similar to that from Apulia than to the nearer population from the Apuan Alps. The results show the usefulness of this molecular approach as a tool for determining taxonomic status and for suggesting faunistic movements in the past millions of years
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