Chromosomal Locations of a Non-LTR Retrotransposon, < b > < i > Menolird18 < /i > < /b > , in < b > < i > Cucumis melo < /i > < /b > and < b > < i > Cucumis sativus < /i > < /b > , and Its Implication on Genome Evolution of < b > < i > Cucumis < /i > < /b > Species

Mobile elements are major regulators of genome evolution through their effects on genome size and chromosome structure in higher organisms. Non-long terminal repeat (non-LTR) retrotransposons, one of the subclasses of transposons, are specifically inserted into repetitive DNA sequences. While studies on the insertion of non-LTR retrotransposons into ribosomal RNA genes and other repetitive DNA sequences have been reported in the animal kingdom, studies in the plant kingdom are limited. Here, using FISH, we confirmed thatMenolird18, a member of LINE (long interspersed nuclear element) in non-LTR retrotransposons and found inCucumis melo, was inserted into ITS and ETS (internal and external transcribed spacers) regions of 18S rDNA in melon and cucumber. Beside the 18S rDNA regions,Menolird18 was also detected in all centromeric regions of melon, while it was located at pericentromeric and sub-telomeric regions in cucumber. The fact that FISH signals ofMenolird18 were found in centromeric and rDNA regions of mitotic chromosomes suggests thatMenolird18 is a rDNA and centromere-specific non-LTR retrotransposon in melon. Our findings are the first report on a non-LTR retrotransposon that is highly conserved in 2 different plant species, melon and cucumber. The clear distinction of chromosomal localization ofMenolird18 in melon and cucumber implies that it might have been involved in the evolutionary processes of the melon (C. melo) and cucumber (C. sativus) genomes.Cytogenet Genome...

Source: Cytogenetic and Genome Research - November 10, 2020 Category: Genetics & Stem Cells Source Type: research