caa a22 4500 445845228 CHVBK 20180317145356.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s10709-011-9546-4 doi (NATIONALLICENCE)springer-10.1007/s10709-011-9546-4 Karyotype analysis of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) reveals a large X chromosome with rRNA and histone gene families [Elektronische Daten] [Jana Novotná, Jan Havelka, Petr Starý, Petr Koutecký, Magda Vítková] The Russsian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a worldwide pest of cereals. Despite its economic importance, little is known about its genome. Here we investigated physical genomic features in RWA by karyotype analysis using differential staining with AgNO3, CMA3, and DAPI, by chromosomal localization of ribosomal DNA (rDNA), H3 and H4 histone genes, and the "arthropod” telomeric sequence (TTAGG)n using fluorescence in situ hybridization (FISH), and by measuring the RWA genome size using flow cytometry. The female karyotype, 2n=10, is composed of four autosome pairs and a pair of X chromosomes, whereas the male karyotype, 2n=9, has a single X. The X chromosome is the largest element in the karyotype. All three molecular markers used, i.e., 18S rRNA and both H3 and H4 probes are co-localized at one end of the X chromosome. The FISH probes revealed that the AgNO3-positive bridge between two prometaphase X chromosomes of females, which is believed to be responsible for the elimination of one X chromosome in aphid oocytes determined to undergo male development, contains clusters of both histone genes, in addition to an rDNA cluster. Interestingly, RWA lacks the (TTAGG)n telomeric sequence in its genome, in contrast to several previously investigated aphid species. Additionally, we compared female and male genome sizes. The female genome size is 2C=0.86pg, whereas the male genome size is 2C=0.70pg. The difference between the DNA content in the two genders suggests that the RWA X chromosome occupies about 35% of the female haploid genome (1C=0.43pg), which makes it one of the largest sex chromosomes in the animal kingdom. Springer Science+Business Media B.V., 2011 Diuraphis noxia nationallicence Karyotype nationallicence Genome size nationallicence rDNA nationallicence Histone gene nationallicence Telomeres nationallicence Novotná Jana Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut Havelka Jan Institute of Entomology, Biology Centre ASCR, Branišovská 31, 370 05, České Budějovice, Czech Republic aut Starý Petr Institute of Entomology, Biology Centre ASCR, Branišovská 31, 370 05, České Budějovice, Czech Republic aut Koutecký Petr Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut Vítková Magda Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut Genetica Springer Netherlands 139/3(2011-03-01), 281-289 0016-6707 139:3<281 2011 139 10709 https://doi.org/10.1007/s10709-011-9546-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10709-011-9546-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Novotná Jana Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut NATIONALLICENCE 700 1- Havelka Jan Institute of Entomology, Biology Centre ASCR, Branišovská 31, 370 05, České Budějovice, Czech Republic aut NATIONALLICENCE 700 1- Starý Petr Institute of Entomology, Biology Centre ASCR, Branišovská 31, 370 05, České Budějovice, Czech Republic aut NATIONALLICENCE 700 1- Koutecký Petr Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut NATIONALLICENCE 700 1- Vítková Magda Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic aut NATIONALLICENCE 773 0- Genetica Springer Netherlands 139/3(2011-03-01), 281-289 0016-6707 139:3<281 2011 139 10709 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer