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Author Ruiz Estévez, Mercedes ♦ Badisco, Liesbeth ♦ Broeck, Jozef Vanden ♦ Perfectti, Francisco ♦ López León, María Dolores ♦ Cabrero, Josefa ♦ Camacho, Juan Pedro M.
Source SpringerLink
Content type Text
Publisher Springer Berlin Heidelberg
File Format PDF
Copyright Year ©2014
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Life sciences; biology
Subject Keyword B chromosome ♦ Gene expression ♦ qPCR ♦ rDNA ♦ rRNA genes ♦ Cell Biology ♦ Biochemistry ♦ Microbial Genetics and Genomics ♦ Plant Genetics & Genomics ♦ Animal Genetics and Genomics
Abstract The genetic inertness of supernumerary (B) chromosomes has recently been called into question after finding several cases of gene activity on them. The grasshopper Eyprepocnemis plorans harbors B chromosomes containing large amounts of ribosomal DNA (rDNA) units, some of which are eventually active, but the amount of rRNA transcripts contributed by B chromosomes, compared to those of the standard (A) chromosomes, is unknown. Here, we address this question by means of quantitative PCR (qPCR) for two different ITS2 amplicons, one coming from rDNA units located in both A and B chromosomes (ITS2A+B) and the other being specific to B chromosomes (ITS2B). We analyzed six body parts in nine males showing rDNA expression in their B chromosomes in the testis. Amplification of the ITS2B amplicon was successful in RNA extracted from all six body parts analyzed, but showed relative quantification (RQ) values four orders of magnitude lower than those obtained for the ITSA+B amplicon. RQ values differed significantly between body parts for the two amplicons, with testis, accessory gland and wing muscle showing threefold higher values than head, gastric cecum and hind leg. We conclude that the level of B-specific rDNA expression is extremely low even in individuals where B chromosome rDNA is not completely silenced. Bearing in mind that B chromosomes carry the largest rDNA cluster in the E. plorans genome, we also infer that the relative contribution of B chromosome rRNA genes to ribosome biogenesis is insignificant, at least in the body parts analyzed.
ISSN 16174615
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2014-07-05
Publisher Place Berlin/Heidelberg
e-ISSN 16174623
Journal Molecular and General Genetics MGG
Volume Number 289
Issue Number 6
Page Count 8
Starting Page 1209
Ending Page 1216


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Source: SpringerLink