Exogenous DNA sequences were introduced into the Drosophila germ line. A rosy transposon (ry1), constructed by inserting a chromosomal DNA fragment containing the wild-type rosy gene into a P transposable element, transformed germ line cells in 20 to 50 percent of the injected rosy mutant embryos. Transformants contained one or two copies of chromosomally integrated, intact ry1 that were stably inherited in subsequent generations. These transformed flies had wild-type eye color indicating that the visible genetic defect in the host strain could be fully and permanently corrected by the transferred gene. To demonstrate the generality of this approach, a DNA segment that does not confer a recognizable phenotype on recipients was also transferred into germ line chromosomes.

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Genetic Transformation of Drosophila with Transposable Element Vectors

The T4 gene encodes the AIDS virus receptor and is expressed in the immune system and the brain.

In most higher organisms, DNA is modified after synthesis by the enzymatic conversion of many cytosine residues to 5-methylcytosine. For several years, control of gene activity by DNA methylation has been recognized as a logically attractive possibility, but experimental support has proved elusive. However, there is now reason to believe, from recent studies, that DNA methylation is a key element in the hierarchy of control mechanisms that govern vertebrate gene function and differentiation.

https://science.sciencemag.org/content/sci/210/4470/604.full.pdf

DNA methylation and gene function

Detection of mRNAs in sea urchin embryos by in situ hybridization using asymmetric RNA probes

Until recently, it has been impossible to approach learning with the techniques of cell biology. During the past several years, elementary forms of learning have been analyzed in higher invertebrates. Their nervous systems allow the experimental study of behavioral, neurophysiological, morphological, biochemical, and genetic components of the functional (plastic) changes underlying learning. In this review, we focus primarily on short-term sensitization of the gill and siphon reflex in the marine mollusk, Aplysia californica. Analyses of this form of learning provide direct evidence that protein phosphorylation dependent on cyclic adenosine monophosphate can modulate synaptic action. These studies also suggest how the molecular mechanisms for this short-term form of synaptic plasticity can be extended to explain both long-term memory and classical conditioning.

https://science.sciencemag.org/content/sci/218/4571/433.full.pdf

Molecular Biology of Learning: Modulation of Transmitter Release.

Isolation of transforming DNA: cloning the hamster aprt gene.

A single gene encodes multiple neuropeptides mediating a stereotyped behavior

Transformation, or DNA-mediated gene transfer, permits the introduction of new genetic information into a cell and frequently results in a change in phenotype. The transforming DNA is ultimately integrated into a recipient cell chromosome. No unique chromosomal locations are apparent, different lines contain the transforming DNA on different chromosomes. Expression of transformed genes frequently results in the synthesis of new polypeptide products which restore appropriate mutant cells to the wild-type phenotype. Thus transformation provides an in vivo assay for the functional role of DNA sequence organization about specific genes. Transforming genes coding for selectable functions, such as adenine phosphoribosyltransferase or thymidine kinase, have now been isolated by utilizing transformation in concert with molecular cloning. Finally, transformation may provide a general approach to the analysis of complex heritable phenotypes by permitting the distinction between phenotypic changes without concomitant changes in DNA and functional genetic rearrangements.

https://science.sciencemag.org/content/sci/209/4463/1414.full.pdf

James F. Jackson

Papers

Isolation of transforming DNA: cloning the hamster aprt gene.

A single gene encodes multiple neuropeptides mediating a stereotyped behavior

Altering genotype and phenotype by DNA-mediated gene transfer

A family of genes that codes for ELH, a neuropeptide eliciting a stereotyped pattern of behavior in Aplysia

Stable and unstable expression of genes in dna transformed cells