Search results for "Radiation Genetics"
showing 5 items of 5 documents
Eradicating Mosquitoes using Translocations
1969
CHROMOSOMAL translocations have been suggested1,2 as useful mechanisms for genetic control: translocation heterozygotes produce fewer offspring because some of their gametes do not receive a full chromosomal complement. The resultant semisterility has been observed in many plants and animals, chiefly after irradiation or other treatments of laboratory stocks but only rarely in natural populations. Spontaneous translocations originating in a field population are usually eliminated3 quickly because of the lower productivity they confer on the heterozygotes. They can become fixed in all members of a population only if it is small and isolated4.
Complementation among developmental mutants in Aspergillus nidulans.
1973
In heterokaryons between pairs of aconidial mutants of Aspergillus nidulans one of the component strains usually shows a striking prevalance in the contribution to the conidial crop. By assuming that the prevailing strain is blocked earlier and the succumbent one later in the process of differentiation, a series of mutations can be arranged in a consistent order. Some mutant strains do not fit the scheme exactly but show a general tendency to be succumbent to “early” mutants and prevalent over the “late” ones. A criterion for arraying genes involved in differentiation according to the order of their physiological action is proposed.
A Red Eye Colour Mutation in Culex pipiens after X-irradiation
1963
FOUR 1–2-day-old males of Culex pipiens were irradiated with a dose of 4,000 r. The mutant ‘red eye’ (r) was isolated from F3 cultures of two of the irradiated males (♂ II and ♂ IV). From male II, there were three red-eyed females which arose out of a single F2 brother–sister mating; from male IV, 80 red-eyed females and one red-eyed male from 14 F2 brother–sister matings. According to the experimental procedure, this means that at least one sperm from male II and at least fourteen sperms from male IV carried the mutation r. Thus, the same mutation was recovered in parallel from two irradiated males. The clustered appearance of the mutation in male IV was presumably caused by the occurrence…
Inherited semisterility for control of harmful insects. II. Degree of sterility and types of translocations in the mosquito Culex pipiens L.
1971
Fur die Anwendung von Semisterilitat infolge von Translokationen zur Bekampfung schadlicher Insekten ist der Grad der Semisterilitat und die Art der zugrundeliegenden Translokation von Bedeutung. Von den bisher untersuchten 124 Translokationen hatten 101 einen Sterilitatsgrad zwischen 10 und 50%, 23 uber 50 bis zu 85%. Mit dem mannlichen Geschlechtsfaktor M gekoppelte Translokationen sind zur Zeit die fur die Praxis am nutzlichsten. Sie treten nicht so haufig auf als erwartet, machen aber doch rund 1/4 aller getesteten Translokationen aus. Es werden Grunde angefuhrt, weshalb M-gekoppelte Translokationen nutzlicher sind.
Inherited semisterility for control of harmful insects. V. Translocations in Culex tritaenio-rhynchus.
1972
Mit unterschiedlichen Dosen von Rontgenstrahlen wurden bei der StechmuckeCulex tritaeniorhynchus chromosomale Aberrationen (vorwiegend reziproke Translokationen) produziert, die von der zweiten Tochtergeneration an einen konstanten Grad von Semisterilitat zeigen. Die Mehrzahl der isolierten Linien zeigte im Durchschnitt eine Letalitat von etwa 50%. Die Variationsbreite innerhalb einer Linie betrug ±10–15%. Durch cytologische Untersuchungen von Prophasechromosomen wurden die geschlechtsbestimmenden Faktoren M und m auf einem der beiden langen Chromosomen lokalisiert.