Abstract
The independent evolution of heteromorphic sex chromosomes in 19 speciesfrom 4 families of flowering plants permits studying X/Y divergenceafter the initial recombination suppression. Here, we documentautosome/Y divergence in the tropical Cucurbitaceae Coccinia grandis,which is ca. 3 myr old. Karyotyping and C-value measurements show thatthe C. grandis Y chromosome has twice the size of any of the otherchromosomes, with a male/female C-value difference of 0.094 pg or 10%of the total genome. FISH staining revealed 5S and 45S rDNA sites onautosomes but not on the Y chromosome, making it unlikely that rDNAcontributed to the elongation of the Y chromosome; recent end-to-endfusion also seems unlikely given the lack of interstitial telomericsignals. GISH with different concentrations of female blocking DNAdetected a possible pseudo-autosomal region on the Y chromosome, andC-banding suggests that the entire Y chromosome in C. grandis isheterochromatic. During meiosis, there is an end-to-end connectionbetween the X and the Y chromosome, but the X does not otherwise differfrom the remaining chromosomes. These findings and a review of plantswith heteromorphic sex chromosomes reveal no relationship betweenspecies age and degree of sex chromosome dimorphism. Its relativelysmall genome size (0.943 pg/2C in males), large Y chromosome, andphylogenetic proximity to the fully sequenced Cucumis sativus make C.grandis a promising model to study sex chromosome evolution.
Dokumententyp: | Zeitschriftenartikel |
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Fakultät: | Medizin |
Themengebiete: | 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit |
URN: | urn:nbn:de:bvb:19-epub-21774-2 |
ISSN: | 1424-8581 |
Allianz-/Nationallizenz: | Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich. |
Sprache: | Englisch |
Dokumenten ID: | 21774 |
Datum der Veröffentlichung auf Open Access LMU: | 22. Okt. 2014, 12:59 |
Letzte Änderungen: | 04. Nov. 2020, 13:02 |