scholarly journals Ribosomal RNA gene copy number and nucleolar-size polymorphisms within and among chicken lines selected for enhanced growth

1998 ◽  
Vol 77 (12) ◽  
pp. 1748-1754 ◽  
Author(s):  
M.H. Su ◽  
M.E. Delany
Keyword(s):  
Ribosomal Rna ◽  
Copy Number ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Ribosomal Rna Gene ◽  
Nucleolar Size

scholarly journals The Responding Site of the Rex Locus of Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 271-276
Author(s):  
Ellen E Swanson
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Ribosomal Rna ◽  
Maternal Effect ◽  
Copy Number ◽  
Mitotic Chromosome ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Rrna Gene ◽  
Chromosome Behavior

ABSTRACT Rex is a dominant, maternal-effect locus in the heterochromatin of the X chromosome Drosophila melanogaster. It causes an early mitotic exchange-like event between heterochromatic elements of an attached- XY in X/attached-XY embryos of Rex mothers. Evidence is presented here that the site of Rex action is the ribosomal RNA gene cluster (the bb locus) only; no other heterochromatin is affected. The Rex locus may be useful in studying regulation of rRNA-gene copy number, mitotic chromosome behavior and heterochromatic function.

scholarly journals Estimating Copy-Number Proportions: The Comeback of Sanger Sequencing

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 283
Author(s):  
Eyal Seroussi
Keyword(s):  
Copy Number ◽  
Sanger Sequencing ◽  
Cytosine Methylation ◽  
Direct Sequencing ◽  
Information Source ◽  
Gene Copy Number ◽  
Cost Effective ◽  
Gene Copy ◽  
Base Editing ◽  
Recent Developments

Determination of the relative copy numbers of mixed molecular species in nucleic acid samples is often the objective of biological experiments, including Single-Nucleotide Polymorphism (SNP), indel and gene copy-number characterization, and quantification of CRISPR-Cas9 base editing, cytosine methylation, and RNA editing. Standard dye-terminator chromatograms are a widely accessible, cost-effective information source from which copy-number proportions can be inferred. However, the rate of incorporation of dye terminators is dependent on the dye type, the adjacent sequence string, and the secondary structure of the sequenced strand. These variable rates complicate inferences and have driven scientists to resort to complex and costly quantification methods. Because these complex methods introduce their own biases, researchers are rethinking whether rectifying distortions in sequencing trace files and using direct sequencing for quantification will enable comparable accurate assessment. Indeed, recent developments in software tools (e.g., TIDE, ICE, EditR, BEEP and BEAT) indicate that quantification based on direct Sanger sequencing is gaining in scientific acceptance. This commentary reviews the common obstacles in quantification and the latest insights and developments relevant to estimating copy-number proportions based on direct Sanger sequencing, concluding that bidirectional sequencing and sophisticated base calling are the keys to identifying and avoiding sequence distortions.

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