caa a22 4500 386399778 CHVBK 20180307112154.0 cr unu---uuuuu 161130e198901 xx s 000 0 eng 10.1017/S0031182000083414 doi S0031182000083414 pii (NATIONALLICENCE)cambridge-10.1017/S0031182000083414 Walliker D. Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN Implications of genetic exchange in the study of protozoan infections [Elektronische Daten] [D. Walliker] Genetic exchange is now known to occur during the life-cycle of many parasitic protozoa, including malaria parasites, coccidia and trypanosomes. The process is studied by making deliberate crosses between cloned organisms differing in clearly defined markers. In malaria parasites, crosses have been made between parasites differing in characters such as isoenzymes, antigens and other proteins, drug sensitivity, and chromosome and other DNA polymorphisms. Crosses are made by transmitting a mixture of gametes of each clone through mosquitoes to allow cross-fertilization to take place, and examining the resulting progeny by cloning for organisms exhibiting non-parental combinations of characters. The inheritance of many characters, such as antigen and protein variants, is in accordance with Mendelian expectations for a haploid organism. Recombination occurs at a higher than expected frequency. Studies on chromosomes have show that crossing-over events commonly occur following meiosis of hybrid zygotes. Repetitive DNA and subtelomeric regions of chromosomes appear to be particularly susceptible to such recombination events. In trypanosomes, crosses between clones of Trypanosoma brucei have shown that hybrids are formed during tsetse fly transmission. The organism appears to be mainly diploid, but some characters including certain chromosomes seem to be inherited in a non-Mendelian manner. Copyright © Cambridge University Press 1989 protozoa nationallicence genetic exchange nationallicence recombination nationallicence Plasmodium spp nationallicence Trypanosoma spp nationallicence Parasitology Cambridge University Press 99/S1(1989-01), S49-S58 0031-1820 99:S1<S49 1989 99 PAR https://doi.org/10.1017/S0031182000083414 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0031182000083414 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Walliker D. Department of Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN NATIONALLICENCE 773 0- Parasitology Cambridge University Press 99/S1(1989-01), S49-S58 0031-1820 99:S1<S49 1989 99 PAR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge