The mode of speciation adopted by a species or group of related species of animals (insects) is clearly determined to a certain extent by the architecture of their genetic system. Chromosome rearrangements, the localization and appearance of the heterochromatin as well as the reproductive relations in sympatric, allopathric speciation and intrograssion process of different species of Chironomidae family are considered. A high chromosome polymorphism and changes in the constitutive heterochromatin are shown as predominant mechanism in the phyletic evolution of some species. Based on an analysis of inversions in different chromosome arms, a chromosome evolution in the "plumosus" group (genus Chironomus) is traced. It was found that the floating inversions in an initial standard karyotype became fixed in a derived karyotype and underlined that the heterochromatin is a dynamic element in the speciation of family Chironomidae. In addition, hybridization tests revealed that pre - and postmating isolating mechanisms were operating in process of formation in different sibling species. It is concluded that the species with overlapping ranges are characterized by more complex chromosome changes, while in species with allopatric speciation there are less chromosome rearrangements. In this case, the distance between the populations is a very important factor as well.

An effective in vitro culture system for mature nodal segments of European plum (Prunus domestica) was established. Several important aspects of regeneration from nodal explants were studied for adaptation of European plum in Bangladesh. Leaf explants were used for callus induction and ½ MS media supplemented with 1.0 mg/l indole butyric acid (IBA) + 0.5 mg/l naphthalene acetic acid (NAA) induced low efficiency callus. The nodal segments of 1.5 cm were cut from young plants, sterilized and established in vitro. The successful cultures were achieved on MS media supplemented with 2-6 mg/l kinetin (KIN); 2, 3, 5 mg/l benzyleaminopurine (BAP) and 4 mg/l KIN combination with 2 mg/l BAP. The highest number of shoot length (1.20 ±0.15 cm), highest number of shoot (3.00±0.35 cm), and highest number of leaf (14.25±1.45) were observed at KIN 4.0 mg/l. The successful multiple shoots were achieved on MS media with 2-6 mg/l KIN, 4 mg/l KIN combination with 2 mg/l BAP. This indicates that, in general, European plum species is very responsive to in vitro regeneration from nodal segment. The shoots from micro cutting were rooted in MS media supplemented with 1.0 mg/l IBA and with 0.5 mg/l BAP; ½ MS media supplemented with 0.5 mg/l IBA + 0.5mg/l NAA and 1.0 mg/l IBA + 0.5 mg/l BAP. Regenerated plantlets successfully acclimatized to grow vigorously with no apparent phenotypic aberrations. In addition, in sense of commercial value without growth hormone achieved great result. Furthermore, the antibacterial activity of extracts of European plum was evaluated against the human pathogenic bacteria Escherichia coli, Klebsiella pneumonia, Protease mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus by agar disc diffusion method. Most of the human pathogens were resistant against commercial disk. But plum fruit extract showed good inhibition zone result (14.25 mm by crude extract against P. aeruginosa and 12.4 mm by dry extract against S. aureus). The positive results of screening of this plum for antibacterial activity forms primary platform for further phytochemical and pharmacological studies.