Nuclear deoxyribonucleic acid characterization of the marine chromophyte Olisthodiscus luteus

Abstract

Nuclear DNA of the marine chromophytic alga Olisthodiscus luteus was analyzed in this study. Reassociation kinetics analysis has shown that 440-nucleotide DNA fragments from the genome of this alga contain 4% foldback, 58% repetitive, and 34% single-copy sequences. Precise analysis using isolated single-copy DNA revealed that Olisthodiscus has a large haploid DNA content of 1.66 x 10(-12) g/cell. For determination of the organization of single-copy and repetitive sequences within this genome, DNA fragments 3000 nucleotides in length were reassociated to C0t= 100 M . s. At this low C0t value 89% of the DNA bound to hydroxylapatite, suggesting that single-copy and repetitive elements are interspersed. The lengths of the duplexed repetitive DNA on these 3000-nucleotide fragments were measured by electron microscopy after digestion with S1 nuclease which removed the unreassociated single-copy DNA regions. Of these repetitive sequences, 68% were shorter than 1200 nucleotide pairs in length and had a modal length of 350 nucleotide pairs. A minor class of longer (to 4000 nucleotide pairs) repetitive sequences was also observed.

HETEROSIGMA AKASHIWO (RAPHIDOPHYCEAE) RESTING CELL FORMATION IN BATCH CULTURE: STRAIN IDENTITY VERSUS PHYSIOLOGICAL RESPONSE 1,2

“…Reassociation kinetic analysis (Ersland and Cattolico 1981) and DNA quantitation (Cattolico 1978) show that the average vegetative Heterosigma cell, harvested in mid‐logarithmic growth, contains 2.13 · 10 − 12 g (1.95 · 10 9 ntp) of DNA. This value represents a haploid (1N) complement.…”

CRYPTIC DIVERSITY IN PHYTOPLANKTON CULTURES IS REVEALED USING A SIMPLE PLATING TECHNIQUE1

“…5). Under the conditions used in these experiments, H. akashiwo has never been observed to undergo sexual reproduction and is believed to be haploid (Ersland andCattolico 1981, Han et al 2002). Given these circumstances, we interpret the observed variation to have been present in the original population and not simply a product of sexual reproduction during the growth of the ''clonal'' lines.…”

“…5). Under the conditions used in these experiments, H. akashiwo has never been observed to undergo sexual reproduction and is believed to be haploid (Ersland and Cattolico 1981, Han et al. 2002).…”

Nuclear Ribosomal Dna Variation Among Ramets and Genets of White Clover

“…Rat carrier DNA was added to some samples to make the total amount of DNA transferred equal 2 J.Lg. Prior to transfer, concentrations ofDNA in samples were determined by Hoechst dye 33258 lIuorescence assays and by UV spectra (Ersland and Cattolico, 1981). Internal controls for effects of reassociation rate-altering contaminants in DNA samples were prepared by including 250 pg pUC 19 plasmid DNA (Pharmacia) in T. repens DNA samples.…”