title: Tandem repeat DNA localizing on the proximal DAPI bands of chromosomes in Larix, Pinaceae.
abstract: Repetitive DNA was cloned from HindIII-digested genomic DNA of Larix leptolepis. The repetitive DNA was about 170 bp long, had an AT content of 67%, and was organized tandemly in the genome. Using fluorescence in situ hybridization and subsequent DAPI banding, the repetitive DNA was localized in DAPI bands at the proximal region of one arm of chromosomes in L. leptolepis and Larix chinensis. Southern blot hybridization to genomic DNA of seven species and five varieties probed with cloned repetitive DNA showed that the repetitive DNA family was present in a tandem organization in genomes of all Larix taxa examined. In addition to the 170-bp sequence, a 220-bp sequence belonging to the same DNA family was also present in 10 taxa. The 220-bp repeat unit was a partial duplication of the 170-bp repeat unit. The 220-bp repeat unit was more abundant in L. chinensis and Larix potaninii var. macrocarpa than in other taxa. The repetitive DNA composed 2.0-3.4% of the genome in most taxa and 0.3 and 0.5% of the genome in L. chinensis and L. potaninii var. macrocarpa, respectively. The unique distribution of the 220-bp repeat unit in Larix indicates the close relationship of these two species. In the family Pinaceae, the LPD (Larix proximal DAPI band specific repeat sequence family) family sequence is widely distributed, but their amount is very small except in the genus Larix. The abundant LPD family in Larix will occur after its speciation.
authors.affiliation: Biological Institute, Faculty of Education, Ehime University, Matsuyama, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hizume
authors.forename: Fukashi
authors.initials: F
authors.lastname: Shibata
authors.forename: Ayako
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Yukie
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Hayashi
authors.forename: Teiji
authors.initials: T
authors.lastname: Kondo
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kondo
authors.forename: Shozo
authors.initials: S
authors.lastname: Zhang
authors.forename: Deyuan
authors.initials: D
authors.lastname: Hong
mesh_terms: D015139:Blotting, Southern; D002871:Chromosome Banding; D005456:Fluorescent Dyes / Q000378:metabolism; D018628:Gene Dosage; D007211:Indoles / Q000378:metabolism; D028221:Larix / Q000235:genetics*; D020080:Tandem Repeat Sequences
chemical_list: D005456:Fluorescent Dyes; D007211:Indoles; C007293:DAPI