Nuclear DNA

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

Human {beta}-globin gene polymorphisms characterized in DNA extracted from ancient bones 12,000 years old

Abstract: Analyzing the nuclear DNA from ancient human bones is an essential step to the understanding of genetic diversity in current populations, provided that such systematic studies are experimentally feasible. This article reports the successful extraction and amplification of nuclear DNA from the P-globin region from 5 of 10 bone specimens up to 12,000 years old. These have been typed for P-globin frameworks by sequencing through two variable positions and for a polymorphic (AT){sub x}(T){sub y} microsatellite 500 bp upstream of the P-globin gene. These specimens of human remains are somewhat older than those analyzed in previous nuclear gene sequencing reports and considerably older than those used to study high-copy-number human mtDNA. These results show that the systematic study of nuclear DNA polymorphisms of ancient populations is feasible. 34 refs., 3 figs., 2 tabs.

Genome Size in Diploids, Allopolyploids, and Autopolyploids of Mediterranean Triticeae

Abstract: Nuclear DNA amount, determined by the flow cytometry method, in diploids, natural and synthetic allopolyploids, and natural and synthetic autopolyploids of the tribe Triticeae (Poaceae) is reviewed here and discussed. In contrast to the very small and nonsignificant variation in nuclear DNA amount that was found at the intraspecific level, the variation at the interspecific level is very large. Evidently changes in genome size are either the cause or the result of speciation. Typical autopolyploids had the expected additive DNA amount of their diploid parents, whereas natural and synthetic cytologically diploidized autopolyploids and natural and synthetic allopolyploids had significantly less DNA than the sum of their parents. Thus, genome downsizing, occurring during or immediately after the formation of these polyploids, provides the physical basis for their cytological diploidization, that is, diploid-like meiotic behavior. Possible mechanisms that are involved in genome downsizing and the biological significance of this phenomenon are discussed.

Mitochondrial DNA in beta-cells is a sensitive target for damage by nitric oxide.

Abstract: Increasing evidence indicates that nitric oxide (NO) may play a role in immune-mediated injury to beta-cells. One site for the action of this agent is the mitochondrion. Although the exact targets for damage within this organelle have yet to be fully elucidated, a potential location for injury is mitochondrial DNA (mtDNA). Therefore, experiments were initiated to evaluate damage to mtDNA caused by NO. Both exogenous NO generation (spermine/NO adduct [sper/NO]) and endogenous production of NO (IL-1beta) were studied. To study the effects of exogenously produced NO, neonatal rat islet cells in monolayers were exposed to varying doses of sper/NO for 30 min. Total cellular DNA was isolated and treated with alkali to produce strand breaks at abasic sites resulting from exposure to NO. Damage to mtDNA was evaluated using a quantitative Southern blot technique. The results showed that sper/NO caused dose-dependent damage to mtDNA. Additionally, mtDNA was found to be more sensitive to injury generated by either source than a similarly sized fragment of nuclear DNA. To evaluate the effects of endogenously produced NO, beta-cell cultures were treated with IL-1beta for 18 h. Other cultures were treated with IL-1beta and an inhibitor of the inducible form of nitric oxide synthase, aminoguanidine. DNA was evaluated as described for the sper/NO studies. IL-1beta caused appreciable damage to mtDNA, and this damage was reduced in mtDNA from cultures treated with IL-1beta and aminoguanidine. These studies show that mtDNA is a sensitive target for NO generated both endogenously and exogenously and that this DNA is more vulnerable to NO-induced damage than nuclear DNA.

Cryptic speciation in Pelobates fuscus (Anura, Pelobatidae): evidence from DNA flow cytometry

Abstract: The amount of nuclear DNA in 173 specimens of Pelobates f. fuscus from 34 localities in Russia, Ukraine, Moldavia and Latvia was determined by DNA e ow cytometry. Two distinct groups with different genome sizes were identie ed. The ranges of the genome size variation in the two groups did not overlap. Geographically, these groups with smaller or larger genome size are distributed in the west and in the east of eastern Europe, respectively.