Highly repetitive (HR), moderately repetitive (MR), single/low-copy (SL) and theoretical single-copy (TS) Cot fractions from P. taeda genotype 7-56 were isolated according to Peterson et al. [29] (also see www.mgel.msstate.edu/seq_names.htm) and sequenced using a GS20 454 pyrosequencer (for sequences see www.pine.msstate.edu/seq.htm).edu/seq.htm
Furthermore, the Xi is associated with the formation of a transcriptionally silenced domain that can be visualized by lack of RNA hybridization with a probe for the Cot-1 fraction of genomic DNA and is thus referred to as a Cot-1 hole [2,3,4].
A human Cot-1 transcriptional domain was also associated with the Xi in a hybrid cell; therefore, the silent nature of the Xi did not impact the expression of the Cot-1 fraction.
By using the Cot-100 fraction to block the repetitive sequence hybridization, both BAC clones generated distinct signals from a single pair of somatic metaphase chromosomes.
The analysis was based on the staining pattern of the Cot-1 RNA fraction (hsRNA), which decorates transcriptionally active areas of DNA, using Cot-1 probe in non-denaturing conditions [33].
It was thought these deficiencies could be partially addressed by sequencing the Cot-selected genomic DNA fraction and reassembling BmiGI.
The ouabain concentration was 0.1 mmol L−1, Na/K/Cl/ COT estimated as bumetamide sensitive fraction of Na efflux into a medium containing 140 mmol L−1 choline chloride and 0.1 mmol L−1 oubain.
Two generalizable approaches to RRL construction have been Cot analysis to isolate the low-copy fraction of a genome [ 1] and screening of restriction enzymes for those that yield the desired fragment size range, in some cases taking advantage of enzyme methyl sensitivity to target certain genomic regions [ 2, 3].
Cot-1 DNA contains the middle repetitive fraction of genomic DNA and when used as a probe for RNA FISH, a depleted region, termed the Cot-1 hole, is associated with the Xi [2], [3], [17].
Typically, a graph is created in which the fraction of reassociated DNA is plotted against the logarithm of Cot (from Cot ~ 0 to Cot values at which reassociation is essentially complete).
Our Cot analysis supports this general tenet as the repetitive fraction of the bald cypress genome is substantial (HR + MR = 90.5%).
