scholarly journals CROSSING OVER IN THE THIRD CHROMOSOMES OF TRIPLOIDS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1930 ◽  
Vol 15 (3) ◽  
pp. 205-252
Author(s):  
Helen Redfield
Keyword(s):  
Drosophila Melanogaster ◽  
Crossing Over ◽  
The Third

scholarly journals THE ORGANIZATION OF GENETIC VARIATION FOR RECOMBINATION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 114 (2) ◽  
pp. 525-547
Author(s):  
Lisa D Brooks ◽  
R William Marks
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Population ◽  
Small Region ◽  
Crossing Over ◽  
Fine Scale ◽  
Response To Selection ◽  
Natural Genetic Variation ◽  
The Third ◽  
Scale Response

ABSTRACT The amount and form of natural genetic variation for recombination were studied in six lines for which second chromosomes were extracted from a natural population of Drosophila melanogaster. Multiply marked second, Χ and third chromosomes were used to score recombination. Recombination in the second chromosomes varied in both amount and distribution. These second chromosomes caused variation in the amount and distribution of crossing over in the Χ chromosome and also caused variation in the amount, but not the distribution, of crossing over in the third chromosome. The total amount of crossing over on a chromosome varied by 12-14%. One small region varied twofold; other regions varied by 16-38%. Lines with less crossing over on one chromosome generally had less crossing over on other chromosomes, the opposite of the standard interchromosomal effect. These results show that modifiers of recombination can affect more than one chromosome, and that the variation exists for fine-scale response to selection on recombination.

scholarly journals THE RELATION OF THE AGE OF THE FEMALE TO CROSSING OVER IN THE THIRD CHROMOSOME OF DROSOPHILA MELANOGASTER

1927 ◽  
Vol 8 (6) ◽  
pp. 689-700 ◽  
Author(s):  
Calvin B. Bridges
Keyword(s):  
Drosophila Melanogaster ◽  
Average Distance ◽  
Internode Length ◽  
Crossing Over ◽  
The Third

The four methods of examining the relation of amount of multiple crossing over to age of mothers agree in showing that the "internode length" or average distance required for double crossing over has changed in a characteristic fashion, giving an M-shaped curve. These changes have not been independent of changes in total recombination but concomitant with them. However, the changes in recombination percentages were far greater than could be accounted for by change in internode length, and the larger factor must be assumed to be changes in the coefficients of crossing over. The amounts of these changes are greatest for the mid-sections of the chromosome and least for the distal sections. The changes in the two limbs are of like amount for equal distances from the center of symmetry in the distribution of simple and multiple crossing over.

scholarly journals SELECTION FOR REDUCED CROSSING OVER IN DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 76 (3) ◽  
pp. 447-451
Author(s):  
Nasr F Abdullah ◽  
Brian Charlesworth
Keyword(s):  
Drosophila Melanogaster ◽  
Regression Coefficient ◽  
Selection Line ◽  
Crossing Over ◽  
Base Population ◽  
The Third ◽  
Significant Difference ◽  
Selection For ◽  
Significant Regression ◽  
Recombination Value

ABSTRACT Selection was practiced for reducing crossing over between the third chromosome genes Sb and H2 of Drosophila melanogaster, the method employed was to select the repulsion double heterozygotes Sb+/+H2 every generation. Two replicate selection lines were maintained. After 24 generations of selection, Line 1 showed no significant difference from the control, although the regression of recombination value on generation was significant. In generation 20, Line 2 had a significantly lower recombination value than the control, as well as having a highly significant regression coefficient. No chromosome rearrangements were involved in the response. It was concluded that there was substantial genic variability in the frequency of crossing over between Sb and H2 in the base population.

scholarly journals A Cluster of Cuticle Protein Genes of Drosophila melanogaster at 65A: Sequence, Structure and Evolution

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1213-1224
Author(s):  
Jean-Philippe Charles ◽  
Carol Chihara ◽  
Shamim Nejad ◽  
Lynn M Riddiford
Keyword(s):  
Drosophila Melanogaster ◽  
Genomic Dna ◽  
Multiple Copy ◽  
Sequence Structure ◽  
Coding Regions ◽  
The Third ◽  
Genetic Complexity ◽  
Genes Encoding ◽  
Cuticle Protein ◽  
Cuticle Proteins

A 36-kb genomic DNA segment of the Drosophila melanogaster genome containing 12 clustered cuticle genes has been mapped and partially sequenced. The cluster maps at 65A 5-6 on the left arm of the third chromosome, in agreement with the previously determined location of a putative cluster encompassing the genes for the third instar larval cuticle proteins LCP5, LCP6 and LCP8. This cluster is the largest cuticle gene cluster discovered to date and shows a number of surprising features that explain in part the genetic complexity of the LCP5, LCP6 and LCP8 loci. The genes encoding LCP5 and LCP8 are multiple copy genes and the presence of extensive similarity in their coding regions gives the first evidence for gene conversion in cuticle genes. In addition, five genes in the cluster are intronless. Four of these five have arisen by retroposition. The other genes in the cluster have a single intron located at an unusual location for insect cuticle genes.

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

Genetics ◽  
1973 ◽  
Vol 74 (3) ◽  
pp. 477-487
Author(s):  
Sumio Minamori ◽  
Kinue Sugimoto
Keyword(s):  
Drosophila Melanogaster ◽  
Crossing Over ◽  
Chromosomal Gene ◽  
Ethyl Methane Sulfonate ◽  
Methane Sulfonate ◽  
Multiple Alleles ◽  
Ethyl Methane ◽  
Extrachromosomal Element ◽  
Polygenic System ◽  
Killing Action

ABSTRACT [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.

Sign in / Sign up

Export Citation Format

Share Document