A Caltech Library Service

DNA Sequence Organization in the Mollusc Aplysia Californica

Angerer, Robert C. and Davidson, Eric H. and Britten, Roy J. (1975) DNA Sequence Organization in the Mollusc Aplysia Californica. Cell, 6 (1). pp. 29-40. ISSN 0092-8674.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


The sequence organization of the DNA of the mollusc Aplysia californica has been examined by a combination of techniques. Close-spaced interspersion of repetitive and single copy sequences occurs throughout the majority of the genome. Detailed examination of the DNA of this protostome reveals great similarities to the pattern observed in the two deuterostome organisms previously examined in detail in this laboratory, Xenopus laevis and Strongylocentrotus purpuratus. Labeled and unlabeled Aplysia DNA were prepared from developing embryos and sheared to a fragment length of 400 nucleotides. The kinetics of reassociation were studied by means of hydroxyapatite chromatography, single-strand-specific S1 nuclease, and optical methods of assay. Aplysia DNA of this fragment length contains at least five resolvable kinetic fractions. One classification of these fractions, listed with their reassociation rate constants (I M−1 sec−1) is: single copy (0.00057), slow (0.047), fast (2.58), very fast (4000), and foldback (> 105). Sequence arrangement was deduced from: the kinetics of reassociation of DNA fragments of length 400 or 2000 nucleotides; the hyperchromicity of reassociated fragments containing duplex regions; the size of duplex regions resistant to S1 nuclease; and the reassociation of labeled fragments of various lengths with short driver fragments. More than 80% of the single copy DNA sequences are interspersed with repetitive sequences. The maximum spacing of the repeats is about 2000 nucleotides, and the average less than 1000. The very fast fraction does not show interspersion with single copy sequences or with other kinetic fractions. The foldback fraction sequences are fairly widely interspersed. The slow fraction sequences are interspersed with the fast fraction, and possibly also with the single copy DNA. The fast fraction is the dominant interspersed repetitive fraction. Its sequences are adjacent to the great majority of the single copy sequences and have an average length of about 300 nucleotides.

Item Type:Article
Related URLs:
URLURL TypeDescription
Additional Information:© 1975 by MIT. Received 8 May 1975, Revised 18 June 1975. This research was supported by a grant from the National Science Foundation and by grants from the National Institutes of Health. RCA was the recipient of a fellowship from the American Cancer Society.
Funding AgencyGrant Number
American Cancer SocietyUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20160811-071702871
Persistent URL:
Official Citation:Robert C. Angerer, Eric H. Davidson, Roy J. Britten, DNA sequence organization in the mollusc aplysia californica, Cell, Volume 6, Issue 1, September 1975, Pages 29-40, ISSN 0092-8674, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:69558
Deposited By: Ruth Sustaita
Deposited On:11 Aug 2016 17:11
Last Modified:03 Oct 2019 10:23

Repository Staff Only: item control page