Genetics and Genomics Commons^™

2: "The Mapping Of Chromosome 16", Norman A. Doggett, Raymond L. Stallings, Carl E. Hildebrand, Robert K. Moyzis

Genomics: Past & Future

Human chromosome 16 is the main focus of the mapping efforts at Los Alamos. The large photomicrograph on these opening pages illustrates the starting point for those mapping efforts, the evaluation of our chromosome-16-specific library of cloned fragments. Among the 23 pairs of human chromosomes, one pair, chromosome 16, is identified by fluorescence in-situ hybridization. Thousands of yellow fluorescent probes derived from the clone library have hybridized to both copies of chromosome 16. The high density and uniform coverage of the fluorescent signals were a strong indication that we could use the library to construct a map of overlapping cloned …

Characterization Of Chemical And Radiation-Induced Dna Damage In The Mdbk Cell Culture System, Jeffrey R. Hincks

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mechanism common to many carcinogens and mutagens is the interaction with cellular DNA. Alkaline elution is a sensitive and commonly used technique to detect cellular DNA damage in the form of DNA single-strand breaks (SSB), DNA-protein cross-links (DPC), and DNA interstrand cross-links (ISC). In the present study, gravity-flow alkaline elution was developed and validated to rapidly detect DNA damage in the MDBK cell culture system by genotoxic agents.

The system was first validated by detecting a dose dependent induction of DNA SSB in cells exposed to 25-1500 rad of X-ray. The assay reliably detected the DNA damage of seven …

Conservation And Variation Of Nucleotide Sequences In Escherichia Coli Strains Isolated From Nature, Lawrence G. Harshman, Monica Riley

Lawrence G. Harshman Publications

A group of Escherichia coli isolates from nature were compared with one another and with laboratory strains of E. coli with respect to size distribution of chromosomal restriction endonuclease fragments and differences in nucleotide sequences in selected small portions of the genomes. The estimated frequency of base substitutions in nucleotide sequences in and near the trp operons of 26 of the 28 E. coli strains examined ranged from 0.008 to 0.066. Nucleotide sequences in or near λ prophage homologs were significantly more variable than the sequences in or near trp, tnaA, and thyA genes. Thus, the λ-homologous regions …

Cytogenetic Test Of Captan And Triethylenemelamine In Mouse Bone Marrow, Stephen M. Fry

Honors Theses

Following a single non-toxic i.p. injection with 0.5 or 1.0 mg triethylenemelamine/kig a significant increase in chromosome aberrations in mouse bone marrow was observed 6, 12, 30, but not 54 h after treatment. A single i.p. injection with 250 mg captan/kig caused up to 68% lethality above controls, but no significant increase in chromosome aberrations after the same time intervals. One metacentric chromosome was observed 6, 30, and 54 h after captan treatment among 300, 300, and 101 metaphase spreads respectively, whereas none appeared in 1495 control spreads.

A Cytological Study Of The Salivary Gland Chromosomes Of The Attached-X Variety Of Drosophila Melanogaster, Jack Schull

Bachelors’ Theses

The detailed study of -the salivary chromosomes of the Diptera has been of great importance in substantiating cytologically the theories of genetics. A noteworthy example of the importance of cytological study is the non-disjunctive phenomenon which has occurred on at least several occasions in the strain of Drosophila melanogaster. Bridges (1913) was the first to report nondisjunction of sex chromosomes which was an important confirmation of the chromosome theory. L. V. Morgan (1922) used the cytological study of the germ cells of Drosophila melanogaster to prove that there was no disjunction of the sex chromosomes in the attached-X strain.