scholarly journals PERSISTENCE OF LETHAL GENES IN JAPANESE NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1970 ◽  
Vol 64 (1) ◽  
pp. 93-106
Author(s):  
Takao K Watanabe ◽  
Chozo Oshima
Genetics ◽  
1976 ◽  
Vol 82 (4) ◽  
pp. 697-702
Author(s):  
Takao K Watanabe ◽  
Tsuneyuki Yamazaki

ABSTRACT Through examination of all available data on lethal and inversion frequencies on the second chromosome in natural populations of Drosophila melanogaster, we have discovered that there is a clear negative correlation between the two quantities. Lethal genes are located more densely on the regions of standard gene arrangement than the inverted regions, and this accounts for the negative correlation. To reveal the underlying mechanism of the phenomena, we have carried out an experiment and found that effect of EMS-induced mutations on the inversion-carrying chromosome is more severe than that on the standard chromosome. We interpret these results as evidence for coadaptation or position-effect within the inversion chromosomes. New mutations within the coadapted gene complex are quickly eliminated from the population and polymorphic inversions are kept free of mutants through selective elimination.


Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1487-1493 ◽  
Author(s):  
Andrew G Clark ◽  
David J Begun

Abstract Differential success of sperm is likely to be an important component of fitness. Extensive variation among male genotypes in competitive success of sperm in multiply mated females has been documented for Drosophila melanogaster. However, virtually all previous studies considered the female to be a passive vessel. Nevertheless, under certain conditions female fitness could be determined by her role in mediating use of sperm from multiple males. Here we ask whether females differ among genotypes in their tendency to exhibit last-male precedence. Competition of sperm from two tester male genotypes (bwD and B3-09, a third-chromosome isogenic line from Beltsville, MD) was quantified by doubly mating female lines that had been rendered homozygous for X, second, or third chromosomes isolated from natural populations. The composite sperm displacement parameter, P2′, was highly heterogeneous among lines, whether or not viability effects were compensated, implying the presence of polymorphic genes affecting access of sperm to eggs. Genetic variation of this type is completely neutral in the absence of pleiotropy or interaction between variation in the two sexes.


Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.


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