Battista Grassi: a zoologist for malaria

Malaria is probably one of the oldest diseases, and it has been the scourge of populations in tropical and temperate-hot areas of the world since antiquity. It is also known by its French term, paludisme although the Italian name, malaria, more accurately describes the disease. The Italian term refers to mala aria, bad air, i.e., the miasmas evaporating from the stagnant waters of marshes, which the ancients believed were the origin of the disease. It was not until the second half of the nineteenth century that scientists started to search for the agent that gave rise to malaria. By then, optical instruments appropriate for this purpose had finally become available, and Robert Koch (1843­1910) and Louis Pasteur (1822­1895) had laid the foundations for scientifically based clinical microbiology

A cytotaxonomic approach of the systematics of Arvicanthis niloticus (Desmarest 1822) (Mammalia Rodentia)

Arvicanthis niloticus (Desmarest 1822) (Mammalia Rodentia) exhibits different karyotypes in different populations throughout its wide distribution area, characterized by diploid numbers ranging from 2n = 62 to 56. A 44 chromosome karyotype is described in one A. niloticus from Somalia. The taxonomic and evolutionary inferences are discussed

Nuclear DNA Content and Morphology of the Karyotype in Certain Palearctic Microchiroptera

SUMMARYHistophotometric evaluation of the DNA content of the post-kinetic nuclei (lymphocytes) has been performed in 8 species of Palearctic Microchiroptera: Rhinolophus ferrumequinum, R. euryale, R. hipposideros, Miniopterus schreibersi, Pipistrellus savii, P. kuhli, Myotys myotis and M. capaccinii. The results obtained are compared with the known data (CAPANNA and CIVITELLI 1970) on the morphology of the karyotype of these species and are discussed whith a view to explaining the relationships between chromosome transformations and variations in DNA content.Considering the entire field studied, the nuclear DNA content is found to be fairly homogeneous: a fact that has been interpreted as proof that this taxonomic group has attained evolutional stability

Morphology and chromosomes of Tatera Lataste 1882 (Rodentia Muridae Gerbillinae) in West Africa

In a sample of the genus Tatera Lataste 1882 from West Africa (Benin and Burkina Faso), we analyzed the cranial and dental morphology and the karyotype (G, R, C and NOR banding). The cranial morphology confirms the attribution of this sample to Tatera kempi Wroughton 1906. An analysis of the dental morphology was also performed but it seems not to offer diagnostic traits. The karyotype described in the present work for T. kempi is comparable with that described for T. hopkinsoni Thomas 1911, supporting the synonymy of these two taxa. In contrast, the karyological results clearly discriminate kempi from both guineae and nigrita, the latter currently considered a synonym. In the karyotype of T. kempi, we found a polymorphism of a small chromosome, which occurs in the three situations: metacentric/metacentric, metacentric/acrocentric and acrocentric/ acrocentric. A similar polymorphism was described for hopkinsoni. The banding shows that the variation of the morphology of the X chromosome in Tatera is related to a pericentric inversion. KEY WORDS: Tatera, rodents, chromosomes, taxonomy, West Africa, evolution

Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n 26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)

The size and shape of the chromosomes, as well as the chromosomal domains that compose them, are determinants in the distribution and interaction between the bivalents within the nucleus of spermatocytes in prophase I of meiosis. Thus the nuclear architecture characteristic of the karyotype of a species can be modified by chromosomal changes such as Robertsonian (RB) chromosomes. In this study we analysed the meiotic prophase nuclear organization of the heterozygous spermatocytes from Mus musculus domesticus 2n=26, and the synaptic configuration of the hexavalent formed by the dependent Rb chromosomes Rbs 6.16, 16.10, 10.15, 15.17 and the telocentric chromosomes 6 and 17. Spreads of 88 pachytene spermatocytes from two males were studied and in all of them five metacentric bivalents, four telocentric bivalents, one hexavalent and the XY bivalent were observed. About 48% of the hexavalents formed a chain or a ring of synapsed chromosomes, the latter closed by synapsis between the short arms of telocentric chromosomes 6 and 17. About 52% of hexavalents formed an open chain of 10 synapsed chromosomal arms belonging to 6 chromosomes. In about half of the unsynapsed hexavalents one of the telocentric chromosome short arms appears associated with the X chromosome single axis, which was otherwise normally paired with the Y chromosome. The cluster of pericentromeric heterochromatin mostly determines the hexavalent’s nuclear configuration, dragging the centromeric regions and all the chromosomes towards the nuclear envelope similar to an association of five telocentric bivalents. These reiterated encounters between these chromosomes restrict the interactions with other chromosomal domains and might favour eventual rearrangements within the metacentric, telocentric or hexavalent chromosome subsets. The unsynapsed short arms of telocentric chromosomes frequently bound to the single axis of the X chromosome could further complicate the already complex segregation of hexavalent chromosomes

Chromosomal and molecular characterization of Aethomys

Aethomys is a common and widespread rodent genus in the African savannas and grasslands. However, its systematics and taxonomy are still unclear as no study has covered the entire range. In fact it might not be a monophyletic genus and perhaps should be split into two subgenera, Micaelamys and Aethomys. In this paper, we present findings based on the cytogenetics and the entire cytochrome b sequence of two species from Zambia (A. kaiseri) and Tanzania (A. chrysophilus), and we compare them with the sequences of a South African species (A. namaquensis) and other allied muroid genera. Comparison of the banded chromosomes revealed complete G-band homology between the autosomes of the two species. However, the X and Y chromosomes clearly differ in size and in C- and G-banding, being much larger in A. kaiseri. Comparison of the cytochrome b sequences places the separation between A. kaiseri and A. chrysophilus at 4.49 Mya, a period of intense speciation in other African muroids. The resulting phylogeny strongly supports the idea of a paraphyletic group, suggesting the need to elevate the previously described subgenera to the genus rank