Journal of Molecular Evolution

, Volume 17, Issue 2, pp 78–84

Evolutionary sequence divergence within repeated DNA families of higher plant genomes

I. Analysis of Reassociation Kinetics
  • Richard S. Preisler
  • William F. Thompson
Article

DOI: 10.1007/BF01732677

Cite this article as:
Preisler, R.S. & Thompson, W.F. J Mol Evol (1981) 17: 78. doi:10.1007/BF01732677

Abstract

The higher proportion of repeated DNA sequences in the garden pea (Pisum sativum) than in the mung bean (Vigna radiata), as well as other differences between these legume genomes, are consistent with a higher rate of sequence amplification in the former. This hypothesis leads to a prediction that repeated sequence families inPisum are mostly heterogeneous, as defined by Bendich and Anderson (1977), whileVigna families are homogeneous. An assay developed by these authors to distinguish between the two types of families, by comparison of reassociation rates at different temperatures, was utilized. The results forVigna defied the predictions of the assay for either homogeneous or hetereogeneous model. Evaluation of the kinetic data in light of the great diversity of repeated family copy numbers in both genomes enabled an interpretation of the results as consistent with hetereogenous families inPisum and homogeneous families inVigna. These tentative conclusions were supported by the results of a thermal denaturation (melting) assay described in the accompanying paper.

Key words

Repeated DNA familiesSequence amplificationHomogeneous and heterogenous familiesDNA reassociation kinetics

Abbreviations used

Cot

the product of molar concentration of DNA nucleotides and time of incubation (mol s/L)

ECot

equivalent

Cot

the value after correction to standard reassociation conditions (120 mM sodium phosphate buffer, 60°C)

(Et)4NCl

tetraethylammonium chloride

Tm

the temperature at which half of the nucleotides in solution are unpaired

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Richard S. Preisler
    • 1
    • 2
  • William F. Thompson
    • 1
    • 2
  1. 1.Department of Plant Biology, Carnegie Institution of WashingtonStanford UniversityStanfordUSA
  2. 2.Department of Biological SciencesStanford UniversityStanfordUSA
  3. 3.Deparment of BiologyUniversity of PennsylvaniaPhiladelphiaUSA