Inherited semisterility for control of harmful insects. II. Degree of sterility and types of translocations in the mosquito Culex pipiens L
Laven, H.; Meyer, E.; Bieniok, R.; Guille, G.; Ohmann, J.
Experientia 27(8): 968-969
1971
ISSN/ISBN: 0014-4754 PMID: 5169617 Document Number: 42509
The results of further tests of irradiated males of Culex pipiens L. for chromosomal translocations causing partial sterility are given in this second paper of a series. F1 males from crosses between irradiated males and normal females were crossed with normal females, and a translocation was considered to be present when more than 10% of the F2 eggs failed to give rise to adults. By this criterion, 124 of 401 F1 males tested contained translocations causing up to 85% sterility, though in a majority (101) the sterility ranged from 11 to 50%. Many lines were maintained for several generations, and in each the sterility varied within 10% of a mean value, showing that the translocations were stable.It is pointed out that three types of chromosomal translocations may be produced in the germ cells of irradiated male mosquitos. One type (TM) is between an autosome and the chromosome with the male-determining allele M, another (Tm) is between an autosome and the chromosome with the female-determining allele m and the third (Ta) is between the two autosomes. TM translocations are the most useful for the purpose of field control, since they are inherited by all male descendants of the irradiated male. Tm and Ta translocations are inherited on average by half the males and half the females of F2 and later generations; it is therefore difficult or impossible to select translocation-bearing mosquitos from a laboratory culture. Examination of the sperm of 81 males with translocations showed that 20 of the translocations were TM, 10 were Tm and 51 were Ta.