Nuclear DNA

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

Mitochondrial DNA-like sequence in the nuclear genome of an akodontine rodent.

Abstract: Initial amplification and sequencing of a 366-bp fragment of the cytochrome b gene by a conserved primer pair (MVZ 03 and MVZ 04) revealed a nonfunctional copy of the gene with two deletions (one of which is 17 bp in length and the other of which is 3 bp in length) in Chroeomys jelskii, a South American akodontine rodent. By means of an alternative primer to MVZ 03--namely, MVZ 05--from the region of the tRNA for glutamic acid, a functional copy of cytochrome b was subsequently amplified. Both primer pairs amplify functional sequence when applied to purified mitochondrial DNA (mtDNA). Restriction-endonuclease digestion of purified mtDNA from C. jelskii did not reveal any additional sets of bands that would suggest heteroplasmy in the mitochondrial genome. When probed with both functional and nonfunctional gene fragments, MboI restriction digests revealed the same pattern, providing further evidence that the nonfunctional copy must be located in the nucleus. Observed differences in the mitochondrial and nuclear sequences from two populations are consistent with a faster rate of change in mtDNA than in nuclear DNA.

Construction and characterisation of a large DNA insert library from the D genome of wheat

Abstract: A large DNA fragment library consisting of 144 000 clones with an average insert size of 119 kb was constructed from nuclear DNA isolated from root and leaf tissue from Triticum tauschii (syn Aegilops tauschii), the D-genome progenitor of wheat The library was made in a binary vector that had previously been shown to stably maintain large inserts of foreign DNA in Escherichia coli The use of root nuclei reduced considerably the proportion of the library containing clones derived from chloroplast DNA Several experimental parameters were investigated and optimised, leading to a high cloning efficiency Only three ligations were needed to construct the library which was estimated to be equivalent to 37 haploid genomes The accuracy of this estimation was demonstrated by screening this library with three well-defined probes One probe containing a glutenin gene sequence identified 5 clones covering at least 230 kb of the Glu-D1 locus and contained the two tightly linked high-molecular-weight glutenin genes Glu-D1x and -D1y Each of the other two single-copy probes derived from the Cre3 cereal cyst nematode resistance gene locus hybridised with 4 clones containing gene sequences encoding nucleotide binding sites and a leucine-rich region This is the first representative large-insert DNA library for wheat, and the results indicated that large molecules of wheat DNA can be efficiently cloned, stably maintained and manipulated in a bacterial system

DNA variation between and within chromosome complements of vicia species

Abstract: 2C nuclear DNA amounts in diploid species of the genus Vicia (x = 5, 6, and 7) range from approximately four to twenty seven picograms. The DNA amount varies independently of the chromosome number and of taxonomic grouping within the genus. Comparisons of the distribution of DNA amounts among chromosomes within the complements show that increase in total nuclear DNA amount within the genus is achieved by equal increments to each chromosome independent of size i.e., small chromosomes acquire the same amount of extra DNA as the large chromosomes. An inevitable consequence of such a pattern of DNA change is that the chromosomes within complements with high DNA amount are more alike in size and DNA content, more symmetrical, than within complements of species with low DNA amount. In a few species the symmetry is confounded as a result of Robertsonian fusion. The equal distribution of extra DNA among chromosomes within a complement has been reported in other genera of flowering plants viz. in Lolium, Festuca and Lathyrus. In all cases there is evidently a severe constraint either upon the way in which the nuclear DNA variation is achieved or else upon its persistence in the face of selection. Since the pattern of change affects the relative sizes of chromosomes within complements we conclude that relative size may itself be of adaptive importance.