English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  Segmental duplications (SD) have been found in genomes of various organisms, often accumulated at the ends of chromosomes. It has been assumed that the sequence homology in-between the SDs allow for ectopic interactions that may contribute to the emergence of new genes or gene variants through recombinatorial events.    Methods   In silico  analysis of the 3D7  Plasmodium falciparum  genome, conducted to investigate the subtelomeric compartments, led to the identification of subtelomeric SDs. Sequence variation and copy number polymorphisms of the SDs were studied by DNA sequencing, real-time quantitative PCR (qPCR) and fluorescent  in situ  hybridization (FISH). The levels of transcription and the developmental expression of copy number variant genes were investigated by qPCR.    Results  A block of six genes of >10 kilobases in size, including  var ,  rif ,  pfmc-2tm  and three hypothetical genes ( n-, o-  and  q-gene ), was found duplicated in the subtelomeric regions of chromosomes 1, 2, 3, 6, 7, 10 and 11 (SD1). The number of SD1 per genome was found to vary from 4 to 8 copies in between different parasites. The intragenic regions of SD1 were found to be highly conserved across ten distinct fresh and long-term cultivated  P. falciparum . Sequence variation was detected in a ≈ 23 amino-acid long hypervariable region of a surface-exposed loop of PFMC-2TM. A hypothetical gene within SD1, the  n-gene , encoding a PEXEL/VTS-containing two-transmembrane protein was found expressed in ring stage parasites. The  n-gene  transcription levels were found to correlate to the number of  n-gene  copies. Fragments of SD1 harbouring two or three of the SD1-genes ( o-gene, pfmc-2tm, q-gene ) were also found in the 3D7 genome. In addition a related second SD, SD2, of ≈ 55% sequence identity to SD1 was found duplicated in a fresh clinical isolate but was only present in a single copy in 3D7 and in other  P. falciparum  lines or clones.    Conclusion   Plasmodium falciparum  carries multiple sequence conserved SDs in the otherwise highly variable subtelomeres of its chromosomes. The uniqueness of the SDs amongst plasmodium species, and the conserved nature of the genes within, is intriguing and suggests an important role of the SD to  P. falciparum .

A highly conserved segmental duplication in the subtelomeres of Plasmodium falciparum chromosomes varies in copy number