Molecular and cytogenetic characterization of an AT-rich satellite DNA family in Urvillea chacoensis Hunz. (Paullinieae, Sapindaceae)

• Published in: Genetica Vol. 136; no. 1; pp. 171 - 177
• Main Authors: Urdampilleta, Juan D., de Souza, Anete Pereira, Schneider, Dilaine R. S., Vanzela, André L. L., Ferrucci, María S., Martins, Eliana R. F.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-05-2009; Springer Nature B.V
• Subjects: Animal Genetics and Genomics; AT Rich Sequence; Base Sequence; Biomedical and Life Sciences; Chromosomes; Cytogenetics; DNA, Plant - chemistry; DNA, Ribosomal - chemistry; DNA, Satellite - chemistry; E coli; Escherichia coli; Evolutionary Biology; Genome, Plant; Heterochromatin; Human Genetics; In Situ Hybridization, Fluorescence; Life Sciences; Microbial Genetics and Genomics; Molecular Sequence Data; Plant Genetics and Genomics; Sapindaceae - genetics; Satellite DNA; FISH; DAPI; Heterochromatin; Karyotype
• ISSN: 0016-6707; 1573-6857
• DOI: 10.1007/s10709-008-9332-0

Urvillea chacoensis
is a climber with 2
n
 = 22 and some terminal AT-rich heterochromatin blocks that differentiate it from other species of the genus. The AT-rich highly repeated satellite DNA was isolated from
U. chacoensis
by the digestion of total nuclear DNA with
Hin
dIII and
Xba
I and cloned in
Escherichia coli
. Satellite DNA structure and chromosomal distribution were investigated. DNA sequencing revealed that the repeat length of satDNA ranges between 721 and 728 bp, the percentage of AT-base pairs was about 72–73% and the studied clones showed an identity of 92.5–95.9%. Although this monomer has a tetranucleosomal size, direct imperfect repetitions of ~180 bp subdividing it in four nucleosomal subregions were observed. The results obtained with FISH indicate that this monomer usually appears distributed in the terminal regions of most chromosomes and is associated to heterochromatin blocks observed after DAPI staining. These observations are discussed in relation to the satellite DNA evolution and compared with other features observed in several plant groups.