Isolation of rapidly evolving genomic sequences: construction of a differential library and identification of a human DNA fragment that does not hybridize to chimpanzee DNA.

A differential library enriched in rapidly evolving human genomic sequences was obtained by phenol-enhanced hybridization of human genomic DNA with an excess of chimpanzee DNA. A DNA fragment 110 bp in length that did not hybridize to either chimpanzee or other primate DNA was identified in this library. It was shown to be a substantially diverged member of the human beta satellite family of tandem repeats.

[Molecular genetic study of the cut locus of Drosophila melanogaster. V. The suffix sequence found in the locus is involved in the 3'-end maturation of different Drosophila mRNAs].

The nucleotide sequences of 8 genomic and 2 mRNA copies of the suffix were studied. It was found that this short repeat (265 bp) forms the last exon (73 bp) in different developmentally regulated Drosophila genes. The functioning genes contain short insertions carrying polyadenylation signals and polyadenylation sites at the same position of the suffix.

[Selection and some properties of recombinant clones of lambda bacteriophage containing structural genes of Drosophila melanogaster].

The lambdagt clones containing fragments of D. melanogaster genome were prepared and characterized by hybridization of their DNA with complementary RNA synthesized on the lambdagt DNA, C fragment of lambdagt DNA and total D. melanogaster DNA, and also with mRNA and a stable cytoplasmic poly(A)-RNA both isolated from D.

Replication of chromosomal DNA in diploid Drosophila melanogaster cells cultured in vitro.

Replication rate and replicon sizes in chromosomal DNA of in vitro cultured diploid D. melanogaster cells were determined using autoradiography of 3H-thymidine labeled DNA. Synthesis of DNA in euchromatic and heterochromatic regions of Drosophila diploid cells occurs at different periods of the S phase which last 10 h.

[Rate of DNA synthesis and the size of replication units in cell culture of Drosophila melanogaster].

The rate of DNA replication and the size of replication units was examined by means of pulse-labeling with 3H-thymidine and DNA autoradiography in the chromsomes of Drosophila melanogaster synchronized cells culture in vitro. The center-to-center distance between adjacent labeled section of DNA fibers was taken for a size of replication unit, i.e.

[Chromosome variability in established cultures of Drosophila melanogaster embryonal cells].

Diploid cell lines with female karyotype for 7 years conserved the normal chromosome set. Tripoid and tetraploid chromosome sets also remained unchanged after two years of cultivation in both sublines. The karyotypes characterized by supernumerary X-chromosomes or deficient for one or more X-chromosomes are predominant among the aneuploids in diploid and euploid lines.

Influence of ecdysterone on the growth of cells and synthesis of macromolecules in established cell lines of Drosophila melanogaster.

Ecdysterone (beta-ecdysone) and 2-deoxy-alpha-ecdysone specifically inhibit the growth of established embryonic cells of D. melanogaster. A preparation of alpha-ecdysone is 100 times less active than ecdysterone.