scholarly journals Peer Review #1 of "Identification of a genome-specific repetitive element in the Gossypium D genome (v0.1)"

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8344
Author(s):  
Hejun Lu ◽  
Xinglei Cui ◽  
Yanyan Zhao ◽  
Richard Odongo Magwanga ◽  
Pengcheng Li ◽  
...  

The activity of genome-specific repetitive sequences is the main cause of genome variation between Gossypium A and D genomes. Through comparative analysis of the two genomes, we retrieved a repetitive element termed ICRd motif, which appears frequently in the diploid Gossypium raimondii (D5) genome but rarely in the diploid Gossypium arboreum (A2) genome. We further explored the existence of the ICRd motif in chromosomes of G. raimondii, G. arboreum, and two tetraploid (AADD) cotton species, Gossypium hirsutum and Gossypium barbadense, by fluorescence in situ hybridization (FISH), and observed that the ICRd motif exists in the D5 and D-subgenomes but not in the A2 and A-subgenomes. The ICRd motif comprises two components, a variable tandem repeat (TR) region and a conservative sequence (CS). The two constituents each have hundreds of repeats that evenly distribute across 13 chromosomes of the D5genome. The ICRd motif (and its repeats) was revealed as the common conservative region harbored by ancient Long Terminal Repeat Retrotransposons. Identification and investigation of the ICRd motif promotes the study of A and D genome differences, facilitates research on Gossypium genome evolution, and provides assistance to subgenome identification and genome assembling.


Author(s):  
Hejun Lu ◽  
Xinglei Cui ◽  
Yanyan Zhao ◽  
Richard Odongo Magwang ◽  
Pengcheng Li ◽  
...  

The activity of genome-specific repetitive sequence is the main cause of the genome variation between Gossypium A and D genomes. Through the comparative analysis of the two genomes, we got a repetitive element (ICRd motif), which repeats massively in the diploid Gossypium raimondii (D5) genome while almost absent in the diploid Gossypium arboreum (A2) genome. We further explored the existence of ICRd motif in G. raimondii, G. arboreum, and two tetraploids (AADD) cotton G. hirsutum and G. barbadense by fluorescence in situ hybridization (FISH), and observed the ICRd motif exists in D5 and D-subgenomes but not in A2 and A-subgenome. The ICRd motif was investigated through its two constituents , a length variable tandem repeat region (TR) and a conservative sequence (CS), which highly repeat and evenly distribute in chromosomes of D5 genome. The ICRd motif was revealed as the common conservative region of ancient LTR-TEs. The identifications and investigation of the ICRd motif promote the study on the A and D genome differences, facilitate the research on the Gossypium genome evolution, and provide assistance to subgenome identification and genome assembling.


2019 ◽  
Author(s):  
Hejun Lu ◽  
Xinglei Cui ◽  
Yanyan Zhao ◽  
Richard Odongo Magwang ◽  
Pengcheng Li ◽  
...  

The activity of genome-specific repetitive sequence is the main cause of the genome variation between Gossypium A and D genomes. Through the comparative analysis of the two genomes, we got a repetitive element (ICRd motif), which repeats massively in the diploid Gossypium raimondii (D5) genome while almost absent in the diploid Gossypium arboreum (A2) genome. We further explored the existence of ICRd motif in G. raimondii, G. arboreum, and two tetraploids (AADD) cotton G. hirsutum and G. barbadense by fluorescence in situ hybridization (FISH), and observed the ICRd motif exists in D5 and D-subgenomes but not in A2 and A-subgenome. The ICRd motif was investigated through its two constituents , a length variable tandem repeat region (TR) and a conservative sequence (CS), which highly repeat and evenly distribute in chromosomes of D5 genome. The ICRd motif was revealed as the common conservative region of ancient LTR-TEs. The identifications and investigation of the ICRd motif promote the study on the A and D genome differences, facilitate the research on the Gossypium genome evolution, and provide assistance to subgenome identification and genome assembling.


Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 706-713 ◽  
Author(s):  
Concha Linares ◽  
Antonio Serna ◽  
Araceli Fominaya

A repetitive sequence, pAs17, was isolated from Avena strigosa (As genome) and characterized. The insert was 646 bp in length and showed 54% AT content. Databank searches revealed its high homology to the long terminal repeat (LTR) sequences of the specific family of Ty1-copia retrotransposons represented by WIS2-1A and Bare. It was also found to be 70% identical to the LTR domain of the WIS2-1A retroelement of wheat and 67% identical to the Bare-1 retroelement of barley. Southern hybridizations of pAs17 to diploid (A or C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) oat species revealed that it was absent in the C diploid species. Slot-blot analysis suggested that both diploid and tetraploid oat species contained 1.3 × 104 copies, indicating that they are a component of the A-genome chromosomes. The hexaploid species contained 2.4 × 104 copies, indicating that they are a component of both A- and D-genome chromosomes. This was confirmed by fluorescent in situ hybridization analyses using pAs17, two ribosomal sequences, and a C-genome specific sequence as probes. Further, the chromosomes involved in three C-A and three C-D intergenomic translocations in Avena murphyi (AC genomes) and Avena sativa cv. Extra Klock (ACD genomes), respectively, were identified. Based on its physical distribution and Southern hybridization patterns, a parental retrotransposon represented by pAs17 appears to have been active at least once during the evolution of the A genome in species of the Avena genus.Key words: chromosomal organization, in situ hybridization, intergenomic translocations, LTR sequence, oats.


Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 2007-2023 ◽  
Author(s):  
Marion S Röder ◽  
Victor Korzun ◽  
Katja Wendehake ◽  
Jens Plaschke ◽  
Marie-Hélène Tixier ◽  
...  

Abstract Hexaploid bread wheat (Triticum aestivum L. em. Thell) is one of the world's most important crop plants and displays a very low level of intraspecific polymorphism. We report the development of highly polymorphic microsatellite markers using procedures optimized for the large wheat genome. The isolation of microsatellite-containing clones from hypomethylated regions of the wheat genome increased the proportion of useful markers almost twofold. The majority (80%) of primer sets developed are genome-specific and detect only a single locus in one of the three genomes of bread wheat (A, B, or D). Only 20% of the markers detect more than one locus. A total of 279 loci amplified by 230 primer sets were placed onto a genetic framework map composed of RFLPs previously mapped in the reference population of the International Triticeae Mapping Initiative (ITMI) Opata 85 × W7984. Sixty-five microsatellites were mapped at a LOD >2.5, and 214 microsatellites were assigned to the most likely intervals. Ninety-three loci were mapped to the A genome, 115 to the B genome, and 71 to the D genome. The markers are randomly distributed along the linkage map, with clustering in several centromeric regions.


1982 ◽  
Vol 24 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Patrick E. McGuire ◽  
Jan Dvořák

Polyploid species of Triticum sensu lato were crossed with Triticum aestivum L. em. Thell. cv. Chinese Spring monotelodisomics or ditelosomics that were monosomic for chromosome 5B. Progeny from these crosses were either euploid, nullisomic for 5B, monotelosomic for a given Chinese Spring chromosome, or nullisomic for 5B and monotelosomic simultaneously. The Chinese Spring telosome in the hybrids permitted the evaluation of autosyndesis of chromosomes of the tested species. In addition, several Chinese Spring eu- and aneuhaploids were produced. Genotypes of T. cylindricum Ces., T. juvenale Thell., T. triunciale (L.) Raspail, T. ovatum (L.) Raspail, T. columnare (Zhuk.) Morris et Sears, T. triaristatum (Willd.) Godr. et Gren., and T. rectum (Zhuk.) comb. nov. were all shown to have suppressive effects on heterogenetic pairing in hybrids lacking 5B or 3AS, whereas T. kotschyi (Boiss.) Bowden had no effect. It was concluded that diploid-like meiosis in these species is due to genetic regulation. A number of these genotypes promoted heterogenetic pairing in the presence of 5B. A model is presented to explain this dichotomous behavior of the tested genotypes. Monotelosomic-3AL haploids had a greater amount of pairing than did euhaploid Chinese Spring, which substantiated the presence of a pairing suppressor(s) on the 3AS arm. Evidence is presented that shows that T. juvenale does not have a genome homologous with the D genome of T. aestivum.


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