Open AccessKaryotype structure, supernumerary chromosomes and heterochromatin distribution suggest a pathway of karyotype evolution in Dactylorhiza (Orchidaceae)
Author(s) -
D’EMERICO SAVERIO,
COZZOLINO ALVATORE,
PELLEGRINO IUSEPPE,
PIG OMENICO,
SCRUGLI ANTONIO
Publication year - 2002
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1046/j.1095-8339.2002.00008.x
Subject(s) - karyotype , biology , heterochromatin , orchidaceae , b chromosome , chromosome , evolutionary biology , genus , genetics , botany , gene
The relationships between Dactylorhiza romana and D. saccifera from southern Italy were analysed. These two species, both with 2 n = 2 x = 40 chromosomes and belonging to different sections of the genus, were distinguishable on the basis of karyotype structure and heterochromatin amounts and distribution. Their C‐banded karyotypes differed considerably. D. saccifera showed most chromosomes with banded regions in the short arms, whereas in D. romana the bands were located mostly at telomeric regions of longer arms. Several individuals of D. romana had one or two very large heterochromatic supernumerary chromosomes. Based on evidence resulting from karyotype structure and heterochromatin distribution in the two species and on the genetic distances derived from the comparison of ITS sequences, it is suggested that D. romana represents a primitive form with respect to D. saccifera and is a possible intermediate step in the evolution of the genus Dactylorhiza from the 42‐chromosome Orchis group. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 85–91.