Nuclear DNA

About: Nuclear DNA is a research topic. Over the lifetime, 3933 publications have been published within this topic receiving 185830 citations.

Nuclear DNA amounts in crustacea

Abstract: 1. 1. Nuclear DNA amounts of thirty-eight species of crustaceans, belonging to three subclasses and seven orders, were determined by cytophotometry or by fluorometric assay. 2. 2. DNA contents vary over a wide range (0·7–22·6 pg haploid). A modal value of about 2·5 pg is typical for many groups. 3. 3. The extreme values are found in groups with peculiar morphological adaptations, and the correlation between specialized morphology and low amounts of DNA in barnacles parallels a comparable trend in other invertebrate groups and in vertebrates.

Dynamics of Nuclear DNA Quantities during Zygote Development in Barley.

Abstract: Quantities of DNA were estimated in the nuclei of mechanically isolated egg and zygote protoplasts in two cultivars of barley using 4[prime],6-diamidino-2-phenylindole staining and microfluorometry. Unlike many previous studies on DNA amounts within the sex cells of flowering plants, we obtained consistent and unambiguous results indicating that the egg and sperm nuclei are at the 1C DNA level (basic haploid amount) at the time of karyogamy. Karyogamy was initiated within 60 min postpollination, and the male chromatin became completely integrated into the egg nucleus within 6 to 7 hr postpollination (hpp). Zygotic nuclear DNA levels began to increase at ~9 to 12 hpp in cultivar Alexis and at 12 to 15 hpp in cultivar Igri. The 4C DNA complement was reached in most zygotes by 22 to 26 hpp in cultivar Alexis and by 23 to 29 hpp in cultivar Igri. These data are fundamental to a better understanding of fertilization and zygote maturation in flowering plants. They are also relevant to studies in which the timing of zygotic DNA replication is of interest, such as ongoing investigations on genetic transformations in barley using the microinjection technique.

Genome size in natural and synthetic autopolyploids and in a natural segmental allopolyploid of several Triticeae species.

Abstract: Nuclear DNA amount (1C) was determined by flow cytometry in the autotetraploid cytotype of Hordeum bulbosum, in the cytologically diploidized autotetraploid cytotypes of Elymus elongatus, Hordeum murinum subsp. murinum and Hordeum murinum subsp. leporinum, in Hordeum marinum subsp. gussoneanum, in their progenitor diploid cytotypes, and in a newly synthesized autotetraploid line of E. elongatus. Several lines collected from different regions of the distribution area of every taxon, each represented by a number of plants, were analyzed in each taxon. The intracytotype variation in nuclear DNA amount of every diploid and autotetraploid cytotype was very small, indicating that no significant changes have occurred in DNA amount either after speciation or after autopolyploid formation. The autotetraploid cytotypes of H. bulbosum and the cytologically diploidized H. marinum subsp. gussoneanum had the expected additive amount of their diploid cytotypes. On the other hand, the cytologically diploidized autotetraploid cytotypes of E. elongatus and H. murinum subsp. murinum and H. murinum subsp. leporinum had considerably less nuclear DNA (10%-23%) than the expected additive value. Also, the newly synthesized autotetraploid line of E. elongatus showed similar reduction in DNA as its natural counterpart, indicating that the reduction in genome size occurred in the natural cytotype during autopolyploidization. It is suggested that the diploid-like meiotic behavior of these cytologically dipolidized autotetraploids is caused by the instantaneous elimination of a large number of DNA sequences, different sequences from different homologous pairs, leading to differentiation of the constituent genomes. The eliminated sequences are likely to include those that participate in homologous recognition and initiation of meiotic pairing. A gene system determining exclusive bivalent pairing by utilizing the differentiation between the two groups of homologues has been presumably superimposed on the DNA reduction process.

RAPD and other PCR-based analyses of plant genomes using DNA extracted from small leaf disks.

Abstract: A nondestructive, early DNA diagnostic system to implement marker-assisted selection in plant breeding programs has been developed. The main components of the system are a rapid and simple DNA microextraction method and fast DNA polymorphism analyses based on site-specific or arbitrary DNA amplification. A small disk (5 mm diameter) is collected from one cotyledon or the first leaf of a young seedling using a common paper punch. Disruption of plant tissues is done by enzymatic digestion of cell walls. This ensures protection from sample-to-sample contamination and uniform DNA yield. DNA isolated from the resulting protoplasts is sufficient to perform a minimum of five and a maximum of 20 PCR reactions/sample. Total DNA, nuclear DNA, and RNA can be analyzed selectively. The system has been tested successfully with eight major crops. Amplification products generated with DNA prepared with this quick procedure are equivalent to those obtained from CsCl-purified DNA. Up to 120 plants can be treated in 2 days and the procedure lends itself to automation. Potential applications in plant breeding will be discussed.

DNA sequence components of the Pinusstrobus nuclear genome

Abstract: The nuclear DNA of Pinusstrobus L. was characterized by whole-genome hydroxyapatite reassociation kinetics. The genome, which is very large, is not well described by partition into three, four, or ...