Climate change is expected to shift species distributions as populations grow in favourable habitats and decline in harsh ones. Montane animals escape warming conditions at low elevation by moving upslope, but may be physiologically constrained by conditions there. Effects of elevation were studied for montane populations of the leaf beetle Chrysomela aeneicollis, where allele frequencies at nuclear genes and the mitochondrion vary along latitudinal and altitudinal gradients. A population presence survey conducted along a steep altitudinal transect (1,600–3,800 m) from 1981 to 2018 revealed that populations expand to low elevation following wet winters and retreat during drought. Quantitative surveys of a 45‐site population network conducted from 2012 to 2018 along multiple altitudinal transects show that when beetles are abundant, population size peaks at 3,135 m, highest altitude populations are at the southern edge of the range, and populations decline and extirpate during drought, especially at low elevation. To examine effects of elevation on measures of performance and fitness, beetles from a genetically introgressed population (Bishop Creek) were examined. In nature, fecundity of females transplanted along natural altitudinal transects was measured, as was thorax cytochrome c oxidase (CytOx) activity. To examine effects of environmental hypoxia independent of other factors limiting persistence at high elevation, development rate and activity of malate dehydrogenase (MDH) were measured for larvae reared under otherwise common garden conditions at low (1,250 m) and high (3,800 m) elevation. In nature, fecundity declined with increasing elevation, independent of air temperature. CytOx activity was higher at high than low elevation, especially for individuals possessing genotypes of southern origin. Laboratory‐reared larvae with southern mitochondrial haplotypes developed equally well at both elevations, but larvae with northern haplotypes developed more slowly at high elevation. MDH activity showed a similar pattern, suggesting that slower development rates at high elevation may be due to reduction in metabolic rate. These findings suggest that physiological effects of environmental hypoxia may contribute to other factors known to restrict insects’ ability to persist at high elevation, ultimately disrupting associated ecological communities. However, some populations may possess genetic variation that allows for local adaption to high elevation. A plain language summary is available for this article.
MicroRNAs (miRNAs) are small non-coding RNAs that function to regulate gene expression at transcriptional and post-transcriptional level. Mature miRNAs are short, usually 18-23 nucleotides (nt) in length, with high homology in the seed region (position 2-8 from the 5′ end of a mature miRNA) within each family. This presents a great challenge when designing assays for quantitation by real-time polymerase chain reaction (PCR). Existing miRNA assays often trade in sensitivity and/or assay performance for specificity. Comparison between two different mature miRNAs with quantitative real-time PCR (qPCR) requires generating standard curves and characterizing PCR efficiency and sensitivity. Here we report a chip-based digital PCR technology. With this technology, we are able to accurately quantitate mature miRNAs without characterizing and optimizing the assay. Briefly, we input the same amount (ratio=1:1) of synthetic hsa-miR-19b and hsa-miR-92a. We then quantitated the miRNAs using reverse transcription followed by quantitative RT-PCR or chip-based QuantStudio™ 3D digital PCR (dPCR). Data from qPCR showed a delta Ct=2.58 between the cDNAs. This converted to a 3.84 fold difference between the two mature miRNAs, which deviated 284% from the input ratio, which equals 1. However, the data from dPCR indicated that the ratio between the amounts of the two mature miRNAs was 0.94 ± 0.02 (SD). Although statistically different, the results from dPCR deviated only 5% from the input ratio. Compared to qPCR, dPCR significantly enhanced the precision in sample quantitation. In summary, our study demonstrated that the chip-based dPCR technology has greatly increased precision in quantitating miRNA samples. The simplified workflow and improved output of dPCR are very useful features in broad applications such as revealing small changes in the miRNA expression levels. Citation Format: Yalei Wu, Victoria Dahlhoff, Lin He, Caifu Chen. Accurate quantitation of micro RNA by chip-based digital PCR. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5241. doi:10.1158/1538-7445.AM2014-5241
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.