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DNA Quantities (dna + quantity)
Selected AbstractsNestling sex ratios in a population of Bluethroats Luscinia svecica inferred from AFLPÔ analysisJOURNAL OF AVIAN BIOLOGY, Issue 1 2000S. Questiau We studied the sex ratio of Bluethroat Luscinia svecica broods using AFLPs. Our aim was to test whether there is a bias towards males that could be explained by sexual selection theories, or conversely, a bias towards females that could help explain the female-biased sex ratio among juveniles observed at a wintering site. The AFLP technique was reliable in sexing the nestlings from even small initial DNA quantities. Given the large number of polymorphic markers that can be obtained for each primer combination, the probability of detecting a W-chromosome-linked fragment is reasonably high. As a consequence, this method could be used in other species for sex-ratio studies and for other genetic purposes. Among 246 nestlings, we found an overall proportion of males of 50.8% at hatching and the sex-ratio variation using broods as independent units was not significantly different from expectation under a binomial distribution. None of the parental and environmental variables tested changed significantly the deviance to the model. Thus, sex determination in the Bluethroat seems to match the classical Mendelian model of a 1:1 sex ratio and cannot explain the biased sex ratio towards juvenile females found at the wintering site. [source] Whole genome amplification from a single cell: a new era for preimplantation genetic diagnosisPRENATAL DIAGNOSIS, Issue 4 2007Serdar Coskun Abstract Preimplantation genetic diagnosis (PGD) is a technique used for determining the genetic status of a single cell biopsied from embryos or oocytes. Genetic analysis from a single cell is both rewarding and challenging, especially in PGD. The starting material is very limited and not replaceable, and the diagnosis has to be made in a very short time. Different whole genome amplification (WGA) techniques have been developed to specifically increase the DNA quantities originating from clinical samples with limited DNA contents. In this review, currently available WGA techniques are introduced and, among them, multiple displacement amplification (MDA) is discussed in detail. MDA generates abundant assay-ready DNA to perform broad panels of genetic assays through its ability to rapidly amplify genomes from single cells. The utilization of MDA for single-cell molecular analysis is expanding at a high rate, and MDA is expected to soon become an integral part of PGD. Copyright © 2007 John Wiley & Sons, Ltd. [source] Noninvasive genetic analysis in birds: testing reliability of feather samplesMOLECULAR ECOLOGY RESOURCES, Issue 3 2002G. Segelbacher Abstract Noninvasive samples are useful for molecular genetic analysis of free-ranging animals. I tested whether moulted feathers collected in the field are a reliable source of DNA for genotyping microsatellite loci. I prescreened extracts for DNA quantity and, using only samples with higher amounts of DNA, obtained reliable genotyping results. Polymerase chain reaction (PCR) amplification success was higher from extracts of plucked feathers than moulted feathers. DNA quantity in larger feathers was higher than that in smaller feathers. This study clearly demonstrates that moulted feathers could be used for genetic studies in birds. [source] New saliva DNA collection method compared to buccal cell collection techniques for epidemiological studiesAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2007Nikki L. Rogers Epidemiological studies may require noninvasive methods for off-site DNA collection. We compared the DNA yield and quality obtained using a whole-saliva collection device (OrageneÔ DNA collection kit) to those from three established noninvasive methods (cytobrush, foam swab, and oral rinse). Each method was tested on 17 adult volunteers from our center, using a random crossover collection design and analyzed using repeated-measures statistics. DNA yield and quality were assessed via gel electrophoresis, spectophotometry, and polymerase chain reaction (PCR) amplification rate. The whole-saliva method provided a significantly greater DNA yield (mean ± SD = 154.9 ± 103.05 ,g, median = 181.88) than the other methods (oral rinse = 54.74 ± 41.72 ,g, 36.56; swab = 11.44 ± 7.39 ,g, 10.72; cytobrush = 12.66 ± 6.19, 13.22 ,g) (all pairwise P < 0.05). Oral-rinse and whole-saliva samples provided the best DNA quality, whereas cytobrush and swab samples provided poorer quality DNA, as shown by lower OD260/OD280 and OD260/OD230 ratios. We conclude that both a 10-ml oral-rinse sample and 2-ml whole-saliva sample provide sufficient DNA quantity and better quality DNA for genetic epidemiological studies than do the commonly used buccal swab and brush techniques.Am. J. Hum. Biol. 19:319,326, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||