The genetic conditions in heterozygous and homozygous populations of Drosophila. II. X-ray induced lethals in a homozygous and a heterozygous population

Sperlich, Diether; Karlik, Anna

doi:10.1007/bf00156139

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…The relative fitness of the homo- very strong fluctuation in the populations, especially between sample 4 and sample 5. This discontinuity in lethal frequencies is different from all other experiments with X-ray induced lethals (Sperlich & Karlik, 1970, 1972Wallace, 1968, p. 199,200;Mukherjee, unpubl. ) or spontaneous lethals (Sperlich & Karlik, unpubl.).…”

Section: Smentioning

confidence: 38%

“…gaster was obtained by Sperlich & Karlik (1970, 1972. They followed the fate of newly introduced genetic material during several generations in experimental populations made homozygous by means of the marker strain technique.…”

Section: Introductionmentioning

confidence: 99%

“…As a rule these lethal marker chromosomes were accepted by homozygous populations but were eliminated from populations with a high degree of heterozygosity. In another experiment (Sperlich & Karlik, 1972), the fate of X-ray induced lethals was observed in a homo-and heterozygous population. Whereas the lethal frequency decreased rather fast in the heterozygous population, it remained at a rather constant level in the homozygous population during the experiment.…”

Section: Introductionmentioning

confidence: 99%

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The genetic conditions in heterozygous and homozygous populations of Drosophila III. EMS induced lethal mutations in homo- and heterozygous populations of Drosophila melanogaster

Karlik

Feuerbach-Mravlag

1977

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A number of experimental populations of Drosophila melanogaster either monochromosomal (e.g. isogenic) or polychromosomal (e.g. random heterozygous) with respect to their second chromosome were obtained by use of the L Cy/Pm marker strain. All populations were initially lethal free. Every other generation was, however, subsequently treated with the mutagen EMS. Between the EMS treatments samples were taken and analyzed with respect to second chromosome lethal frequency. In spite of a great fluctuation in lethal frequencies, the general tendency of the accumulation of recessive lethals was higher in monothan in polychromosomal populations. Allelism tests showed a very high rate of identical lethals in monochromosomal as well as in polychromosomal populations. Hence, some of the induced lethals seem to be heterotie. Viability tests were performed in some of the initial populations and again after EMS treatment in generation 19. The mean viabilities of homozygotes for second chromosomes were rather constant in a polyehromosomal population but were highly reduced in three out of four monochromosomal populations. This, again, may be due to a higher tendency of load accumulation in monochromosomal populations.

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Section: Smentioning

confidence: 38%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The genetic conditions in heterozygous and homozygous populations of Drosophila III. EMS induced lethal mutations in homo- and heterozygous populations of Drosophila melanogaster

Karlik

Feuerbach-Mravlag

1977

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Genetic variation in a semi-natural Drosophila population after a bottleneck I. Lethals, their allelism and effective population size

et al. 1985

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A semi-natural Drosophila melanogaster population was twice forced through a genetic bottleneck and allowed to recover naturally. In one case additional variation was introduced to the recovering population. The percentage of lethal chromosomes, the level of allelism between these lethals, and the effective population size calculated from the allelism of these lethals all rose sharply in the few generations following each bottleneck, though this was not t~,e case in the very first generation. Thereafter this rise decelerated rapidly and never returned to pre-bottleneck levels. Additional introduced variation had little effect. The reasons for and implications of this pattern have been considered.

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Genetic load and viability variation in korean natural populations of Drosophila melanogaster

Choi

1978

Theoret. Appl. Genetics

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Natural populations of Drosophila melanogaster from Anyang and Susac (suburbs of Seoul) have been analyzed with respect to viability variation on the second chromosome. Homozygotes as well as random heterozygotes for wild chromosomes were studied. The frequency of lethal factors was about 16 per cent, that of drastics 26 per cent. The average viability of homozygotes was 0.650 including lethal lines and 0.858 for quasinormals; that for random heterozygotes was 1.125. Allelism tests have been performed for the lethals. The allelism rate turned out to be as high as 0.036 and 0.0214, respectively. Using a formula by Nei, the effective population size can be estimated from these data. Korean D. melanogaster populations proved as small as 2000 to 3000 individuals. No correlation between homozygous and heterozygous viabilities could be found. According to these observations, along with the fact that partly big clusters of identic lethals could be found in the allelism tests, it is concluded that in Korean populations quite a large part of the hard genetic load is balanced. The connection between population size, population structure and associative or genuine overdominance is discussed.

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The genetic conditions in heterozygous and homozygous populations of Drosophila. II. X-ray induced lethals in a homozygous and a heterozygous population

Cited by 4 publications

References 11 publications

The genetic conditions in heterozygous and homozygous populations of Drosophila III. EMS induced lethal mutations in homo- and heterozygous populations of Drosophila melanogaster

The genetic conditions in heterozygous and homozygous populations of Drosophila III. EMS induced lethal mutations in homo- and heterozygous populations of Drosophila melanogaster

Genetic variation in a semi-natural Drosophila population after a bottleneck I. Lethals, their allelism and effective population size

Genetic load and viability variation in korean natural populations of Drosophila melanogaster

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