Maternal and paternal lineages in Albania and the genetic structure of Indo-European populations.

Mitochondrial DNA HV1 sequences and Y chromosome haplotypes (DYS19 STR and YAP) were characterised in an Albanian sample and compared with those of several other Indo-European populations from the European continent. No significant difference was observed between Albanians and most other Europeans, despite the fact that Albanians are clearly different from all other Indo-Europeans linguistically. We observe a general lack of genetic structure among Indo-European populations for both maternal and paternal polymorphisms, as well as low levels of correlation between linguistics and genetics, even though slightly more significant for the Y chromosome than for mtDNA. Altogether, our results show that the linguistic structure of continental Indo-European populations is not reflected in the variability of the mitochondrial and Y chromosome markers. This discrepancy could be due to very recent differentiation of Indo-European populations in Europe and/or substantial amounts of gene flow among these populations.

A novel algorithm for the search of 5S rRNA genes in DNA databases: comparison with other methods and identification of new potential 5S rRNA genes.

We report here a new algorithm for the identification of 5S rRNA genes in DNA databases. Based on an improved version of the general weight matrix method, this search procedure relies on the recognition of three informative regions within 5S rRNA genes, and on the weighted evaluation of the distance between them. As an additional step, the algorithm extends the weight matrix analysis to the full-length 5S rRNA sequence. This combined strategy, which includes a fast, but poorly selective, preliminary search procedure and an auxiliary step, that is slow but highly selective, strongly reduces the number of false positive instances, yielding a total false positive rate of 0.00076%. On the other hand, 97.5% of the 1045 known 5S rRNA genes were correctly recognized by this algorithm, and 29 previously unidentified potential 5S rRNA sequences were uncovered. A detailed analysis of these candidate sequences, including prediction of 5S rRNA secondary structure and checking for the presence of transcriptional termination signals, showed that eight of them correspond to authentic 5S rRNA genes. The performance of this specialized algorithm for the detection of 5S rRNA genes was compared with that of the general hidden Markov model search procedure. Due to their utilization of different filtering rules, the two approaches proved to be highly complementary. Their combined use will thus provide a very effective tool for the detection of dispersed 5S rRNA genes, either active or inactive, in the vertebrate genome.

Identification of new eukaryotic tRNA genes in genomic DNA databases by a multistep weight matrix analysis of transcriptional control regions.

A linear method for the search of eukaryotic nuclear tRNA genes in DNA databases is described. Based on a modified version of the general weight matrix procedure, our algorithm relies on the recognition of two intragenic control regions known as A and B boxes, a transcription termination signal, and on the evaluation of the spacing between these elements. The scanning of the eukaryotic nuclear DNA database using this search algorithm correctly identified 933 of the 940 known tRNA genes (0.74% of false negatives). Thirty new potential tRNA genes were identified, and the transcriptional activity of two of them was directly verified by in vitro transcription. The total false positive rate of the algorithm was 0.014%. Structurally unusual tRNA genes, like those coding for selenocysteine tRNAs, could also be recognized using a set of rules concerning their specific properties, and one human gene coding for such tRNA was identified. Some of the newly identified tRNA genes were found in rather uncommon genomic positions: 2 in centromeric regions and 3 within introns. Furthermore, the presence of extragenically located B boxes in tRNA genes from various organisms could be detected through a specific subroutine of the standard search program.

Isonymy and the genetic structure of Sicily.

The genetic structure of Sicily was analysed through the distribution of surnames of 758,793 users registered in the Italian Telephone Company, corresponding to 371 communes of the island. Estimates of the coefficient of consanguinity due to random isonymy, of Fisher's a, an indicator of abundance of surnames, and of Karlin-McGregor's v, an indicator of immigration rates, were obtained for each commune. Four different estimates of genetic distance between all possible pairs of communes within each province were also obtained, and their relationship with geographic distance was studied. The logarithmic transformation of Lasker's coefficient of relationship showed correlations with the log of geographic distance which range between -0.78 and -0.40; the strongest, for the province of Catania, was attributed to the presence of Mount Etna, and the weakest, for Palermo, to the high population density of this province.

Polymorphic DdeI restriction sites in mitochondrial d-Loop DNA from Emilian blood donors.

We describe two new polymorphic sites identified by DdeI digestion of human mitochondrial D-Loop DNA. Their frequencies were estimated on a random group of 54 unrelated blood donors, born and descending from female ancestors of the Province of Reggio Emilia (Central Emilia, Northern Italy). These newly detected polymorphisms were generated by A to G transitions at positions 16300 and 16482 of mt-DNA. They were found at a 5% frequency in our sample whereas the remaining 95% of the sample exhibited a Cambridge sequence restriction pattern.

[Formation and size of complete families in the high Parma valley, 1750-1924].

PIP: The study represents an attempt to reconstruct fertility rates on families over 3 centuries in 40 parishes in the High Parma Valley, in Central Italy. It was possible to reconstruct family sizes of families who remained stable in their villages for several generations, and it was noted that male mortality amply exceeded female mortality. Because of the death of the father before the mother's 50th birthday, which, for the purpose of this study, is taken as onset of menopause and, hence, of sterility, many families remained incompleted. Mean number of children per family increases from 1750 to the middle 1800s; it then remains stable till the end of the century, to rapidly decrease from that moment on. The highest number of children per family was calculated to be 8 for the period 1800-1849 for women who were 15-19 at time of marriage.^ieng

[Genetic observations on hereditary spherocytosis in some family groups in a region of Mantova north of the Po and/in the province of Parma]. / Osservazioni genetiche sulla sferocitosi ereditaria in alcuni gruppi familiari dell-Oltrepo Mantovano e della provincia di Parma

Hereditary spherocytosis is an haemolitic disease, generally characterized by anaemia, jaundice, and splenomegaly. With reference to data collected in the territory of Quistello, in the Province of Mantova and in the Hospital of the City of Parma, about 280 persons were examined, belonging to the families most affected by hereditary spherocytosis. The results support the hypothesis that the disease is due to an autosomic dominant gene with an almost complete penetrance (0.9). No significant decrease in fitness, measured as a function of fertility, was observed, nor was it possible, from the data examined, to evaluate any correlation between presence of the disease and cases of abortion or perinatal mortality. It is worthy of note that all the observed cases pertain to families that are distributed along the course of the Po River. A biochemical enquiry, based upon an evaluation of the differences in protein composition between the membranes of spherocytes and normal eritrocytes, by electrophoresis on gel of polyacrylamide, gave contrasting results.