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Mutations do not always arise as single events. Many new mutations actually occur in the cell lineage before germ cell formation or meiosis and are therefore replicated premeiotically. The increased likelihood of substitutions caused by these clusters of new mutant alleles can change the fundamental theorem of neutral evolution.
While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier...
As part of our effort to monitor changes in the clinal pattern of P element-associated traits in eastern Australian Drosophila melanogaster, we investigated the genomic P elements of 293 isofemale lines collected in the period 1991–1994 from 45 localities. P elements were present in many copies in all genomes examined, with full-size P and KP element size classes accounting for the large majority...
Some transposable DNA elements in higher organisms are active in somatic cells, as well as in germinal cells. What effect does the movement of DNA elements in somatic cells have on life history traits? It has previously been reported that somatically active P and mariner elements in Drosophila induce genetic damage and significantly reduce lifespan. In this study, we report that the movement of P...
The latitudinal cline in P transposable element-associated characteristics in eastern Australian populations of Drosophila melanogaster has changed between 1986 and 1991–1994. New collections were made in 1991–1994 from localities along the eastern coast of Australia. P element-associated properties of 256 isofemale lines from 43 localities were evaluated using gonadal dysgenesis and/or singed-weak...
Given favorable environmental and demographic conditions, premeiotic clusters of identical mutations can produce a broad distribution of the initial frequency of underdominant alleles. Because of these clusters, new underdominant mutations may not necessarily be as rare in a population as previously assumed. The fixation of underdominant mutations, especially those with low heterozygous fitness, is...
Molecular evidence from mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) supports the existence of genetically different spawning groups of walleye (Stizostedion vitreum) among the Maumee, Sandusky, and Grand rivers that flow into Lake Erie. Three separate regions of the mtDNA molecule (the D-loop region, the NADH dehydrogenase 3, 4, and 4L genes, and the 12S and 16S rRNA...
Evidence is presented in support of the hypothesis that P DNA element movement in somatic cells of Drosophila melanogaster induces genetic damage that significantly reduces lifespan. The lifespan of D. melanogaster males was significantly reduced by the somatic movement of a single P element in the presence of P[ry + Δ2-3](99B) transposase. In addition, the P[ry + SalI](89D) repressor...
The effect of somatic movement of the mariner transposable element on lifespan was measured in Drosophila simulans and Drosophila melanogaster males at 25 o C. In D. simulans this movement significantly decreased lifespan, whereas in D. melanogaster no correlation between transposon movement and lifespan was found. The results in D. simulans support the hypothesis that somatic genetic damage...
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