ABSTRACT
The developmental and the tissue-specific expression of glucosephosphate isomerase (GPI), lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) multilocus isozymes were analyzed in samples of Leuciscus cephalus and the adult patterns compared with those of 8 additional Italian cyprinid species: Alburnus alburnus alborella, Chondrostoma genei, L. lucumonis, L. souffia, Rutilus rubilio, R. erythrophthalmus, Scardinius erythrophthalmus and Tinca tinca, the taxonomic status of many of them being uncertain and highly debated. The spatial and temporal patterns of expression obtained generally agree with literature data. Main exceptions are the single expression of GPI-A* and MDH-A* loci of the liver in L. cephalus and the GPI pattern of the eye in all species examined. Since delayed appearence of the subunits coded by the GPI-B* locus and the very early ontogenetic expression of the sMDH-B* locus were found in L. cephalus, the onset of expression of orthologous loci can vary in related species. Genetic structure comparisons support a high genetic divergence of T. tinca from all other species.
ABSTRACT
The standard karyotype and a wide array of repatterned cytotypes from 21 demes of the double-allotriploid thelytokous Bacillus lynceorum have been analyzed by means of Giemsa, C-banding, and silver-staining techniques. The present study substantially amends the first karyotype description and also analyzes in detail the chromosomal rearrangements to trace their most likely derivation. Bacillus lynceorum cytotypes also provide a well-documented instance of an intraspecific gain of centromeric function. The contribution of three different specific haplosets is particularly evidenced from centromeric heterochromatin pattern and satellite/Ag-NOR locations. In stick insects, both hybridogenetic and parthenogenetic Bacillus hybrids, including B. lynceorum, can utilize the rDNA of all available parental haplosets, although a hierarchical role of the B. rossius genome seems to emerge. Satellite/Ag-NOR patterns, besides clearly allowing the recognition of ancestral parental genomes, also suggest a polyphyletic origin for B. lynceorum, which, to our knowledge, represents the only described karyotype of a trihybrid invertebrate.
