Extrachromosomal element delta in Drosophila melanogaster

Minamori, Sumio; Ito, Kazuko

doi:10.1016/0027-5107(71)90047-9

Cited by 21 publications

(10 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been shown that Sb and s ' lines gradually accumulate their specific deltas over a number of generations in the progeny of males of these lines (MINAMORI 1969b(MINAMORI , 1971(MINAMORI , 1972. Therefore, the induced sensitives were maintained for ten generations at 25"C, and then the amount and kind of accumulated delta were determined by mating C y heterozygous females of these lines to males of Cy/Sb-9 (test for [ab]) and Cy/Sr-20 (test for [a*]).…”

Section: Resultsmentioning

confidence: 99%

“…The extrachromosomal element denoted by delta appears virus-like in damaging host chromosomes. It induces frequent recessive lethal mutations in definite regions of chromosome 2 and dysfunctional spermatozoa carrying a specific homolog of the same chromosome (MINAMORI 1970;MINAMORI and ITO 1971). Most lethals (about 82%) induced by delta are located on the right arm, especially in the Lobe region (2-72.0).…”

mentioning

confidence: 99%

“…The Sb retains [delta b] , symbolized as [ Sb] , and is sensitive to the killing action of this delta but not to [delta r], symbolized as [S']; S' retains [SI. ] and is sensitive to both [ab] and [ar] ; ID is insensitive to either delta (MINAMORI et al 1970;MINAMORI 1971). [Sb] is transmitted by Sb-carrying females to their progeny, but transmission through the males cannot be demonstrated.…”

mentioning

confidence: 99%

“…1972). Based on this fact, the entity delta was assumed to be a copy of a chromosomal gene or a certain agent integrated inseparably into the chromosome (MINAMORI 1971(MINAMORI , 1972. In this study these alternatives are examined.…”

mentioning

confidence: 99%

“…cif. ), and the ST chromosome was Sr-20 (isolated in 1966;MINAMORI 1971). These sensitive lines steadily retained an appreciable amount of each specific delta; the Sb lines retained [ab], and the Sr retained [a.].…”

mentioning

confidence: 99%

See 4 more Smart Citations

EXTRACHROMOSOMAL ELEMENT DELTA IN DROSOPHILA MELANOGASTER. IX. INDUCTION OF DELTA-RETAINING CHROMOSOME LINES BY MUTATION AND GENE MAPPING

Minamori

Sugimoto

1973

Genetics

View full text Add to dashboard Cite

[Delta b], symbolized as [δb], is retained by Sb chromosome lines and transmitted through the females to their progeny. Transmission through the males is not directly demonstrable (Minamori 1969a). [delta r], symbolized as [δr], is retained by Sr chromosome lines and transmitted biparentally (Minamori 1971). The multiplication of delta is suppressed at low temperature. All descendant lines derived from Sb-carrying or Sr-carrying flies in which the presence of delta cannot be demonstrated gradually accumulate their specific delta factors over many generations (Minamori 1969b, 1972). The delta factors and the sensitive chromosomes are inseparably associated. This observation led to the assumption that delta may be a copy of a chromosomal gene or a certain agent integrated into the chromosome (Minamori 1972). This assumption was examined in the present study by experiments designed to induce delta-retaining sensitive chromosomes, and to map the gene(s) responsible for delta-retention and/or for sensitivity to the killing action of delta factor. One sensitive chromosome which retained [δb] (Sb chromosome) was obtained in the presence of [δb] out of 2492 insensitive chromosomes which retained no delta; in addition one Sb chromosome was obtained in the presence of [δr] out of 2131 insensitives. The latter finding suggests that Sb might be induced by a mutation caused by [δb] or [δr], but not by integration of either delta into the chromosome. Four Sb chromosomes and one sensitive chromosome which retained [δr] (Sr chromosome) were obtained out of 1970 insensitives when males carrying the chromosome were fed an alkylating mutagen, ethyl methane sulfonate (EMS). The location of delta-retaining genes was examined by crossing-over experiments employing eight Sb and five Sr chromosomes. The genes on these chromosomes were found to be located in the same region or near one another. The gene for [δb], symbolized as Dab, and the gene for [δr], symbolized as Dar, are assumed to be multiple alleles of a locus at 2-24.9. The sensitivity of the chromosomes was modified appreciably by recombination; hence, the genes controlling this trait are assumed to be a polygenic system. The findings obtained in this study lead to the hypothesis that delta may be produced by a chromosomal gene (Da) and transmitted extrachromosomally.

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations