The Relation of an Inversion System to Recombination in Wild Populations

Epling, Carl; Mitchell, Donald F.; Mattoni, R. H. T.

doi:10.1111/j.1558-5646.1957.tb02890.x

Cited by 22 publications

(2 citation statements)

References 26 publications

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“…Dobzhansky (1943Dobzhansky ( , 1947a found that natural selection was present in at least two of three St. Jacinto (California) populations that he examined, because of seasonal changes in chromosomal rearrangements. Similar cyclic changes have also been recorded for D. funebris populations Tiniakov, 1945, 1946) and other Drosophila species (Dobzhansky et al, 1964;Epling et al, 1957). These changes cannot have been caused by genetic drift, because they were cyclic and followed the seasonal changes every year.…”

Section: There Are Some Other Relevant Questionssupporting

confidence: 75%

“…Powell (1992) has reported that other Californian and North American populations do not show these annual cyclic changes. At Keen Camp, 15 miles from the populations referred to above and with a different rainfall level, there were no seasonal variations (Dobzhansky, 1943(Dobzhansky, , 1947bEpling et al, 1957). Crumpacker and Williams (1974) studied two populations in north and south of Denver (Colorado), and found that in the northern population rearrangement frequencies were constant during the year, while in the southern population although the overall frequencies were similar to the northern population they had seasonal cycles, with the AR rearrangement reaching high values in spring and early summer but declining to its lowest frequency at the end of summer, reaching a new maximum in autumn.…”

Section: There Are Some Other Relevant Questionsmentioning

confidence: 93%

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Detection of stabilizing selection in favor of the Santa Cruz homokaryotype in Drosophila pseudoobscura populations from the high plateau of the Colombian Andes

Álvarez¹,

Ruiz‐García²,

Guerrero³

et al. 2002

Genet. Mol. Res.

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Chromosome 3 rearrangements were studied in five Drosophila pseudoobscura populations from the high plateau of the Colombian Andes. As in previous studies, the Santa Cruz and Tree Line rearrangements were predominant in these populations, but for the first time other rearrangements such as the Olympic, Cuernavaca and a rearrangement similar to the endemic Mexican Amecameca rearrangement were also discovered. Researchers in the early 1960's showed that Colombian D. pseudoobscura populations were not in accordance with Carson's theory. They found a special heterotic system in this geographically isolated population. Our current results do not support these findings but instead favor Carson's theory, because in practically all the populations studied the homokaryotype excess was close to fixation. These new results indicate that some stabilizing selective pressures in favor of the homokaryotypes (especially Santa Cruz) have appeared in the Colombian plateau during the last 10-12 years. These new changes may be related to deforestation and habitat destruction by human beings and/or climatic changes motivated by the El Niño phenomenon. Genetic heterogeneity between populations was not significant and there was no isolation-by-distance between them, findings which are contrary to those observed in some North American populations and which show that the Colombian populations now have rigid genetic systems. The frequency of the Santa Cruz rearrangement

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Section: There Are Some Other Relevant Questionssupporting

confidence: 75%

Section: There Are Some Other Relevant Questionsmentioning

confidence: 93%

Detection of stabilizing selection in favor of the Santa Cruz homokaryotype in Drosophila pseudoobscura populations from the high plateau of the Colombian Andes

Álvarez¹,

Ruiz‐García²,

Guerrero³

et al. 2002

Genet. Mol. Res.

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Chromosomal Differentiation in Clarkia Dudleyana

Snow

1960

American J of Botany

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Snow, Richard. (U. California, Davis.) Chromosomal differentiation in Clarkia dudleyana. Amer. Jour. Bot. 47 (4) : 302—309. Illus. 1960.—Clarkia dudleyana (n=9) is a common, colonial annual of the early‐summer California flora. Of 275 individuals, derived from 9 natural populations and their garden‐grown representatives, 17.1% were heterozygous for reciprocal translocations. Supernumerary chromosomes were also found in about 2% of the plants examined. The translocation heterozygotes are not distributed regularly over the species range but are concentrated near the geographical center of distribution. Most of the populations contained none or only a few heterozygotes, but in one colony 69% of 42 plants sampled were heterozygous. Judging from the meiotic metaphase associations observed, at least 5 different chromosome arrangements are present at this locality. Hybrids between colonies have invariably been translocation heterozygotes, the largest association found in such hybrids being a chain of all 18 chromosomes (a potential ring of 18). No correlation is evident between geographical separation and degree of cytological differentiation. Heterozygotes with smaller rings of 4 or 6 chromosomes, whether from natural populations or resulting from interpopulation hybridization, are highly fertile owing to the regular alternate disjunction of the chromosomes of the rings. In the larger rings of 12 to 18 chromosomes, derived from interpopulation crosses, segregation is much more irregular and leads to high sterility. It is possible that at least in some localities the heterozygotes enjoy a selective advantage over their homozygous sibs. It is also postulated that homozygosity for a particular chromosome arrangement may be selectively favored in a certain habitat, as a result of a position effect attendant upon placing formerly non‐linked genes in the same linkage group through reciprocal translocation. The high degree of chromosomal differentiation between some populations of this species suggests that the complex heterozygotes of Oenothera have arisen as a result of hybridization of cytologically differentiated races.

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Evolutionary Oscillations in Drosophila pseudoobscura

Dobzhansky¹

1971

Ecological Genetics and Evolution

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The Relation of an Inversion System to Recombination in Wild Populations

Cited by 22 publications

References 26 publications

Detection of stabilizing selection in favor of the Santa Cruz homokaryotype in Drosophila pseudoobscura populations from the high plateau of the Colombian Andes

Detection of stabilizing selection in favor of the Santa Cruz homokaryotype in Drosophila pseudoobscura populations from the high plateau of the Colombian Andes

Chromosomal Differentiation in Clarkia Dudleyana

Evolutionary Oscillations in Drosophila pseudoobscura

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