Widespread distribution of extensive chromosomal fragmentation in ciliates.
Mol Biol Evol
; 18(7): 1372-7, 2001 Jul.
Article
en En
| MEDLINE
| ID: mdl-11420375
ABSTRACT
Ciliates are a diverse group of eukaryotes characterized by their division of nuclear function into a "germ line" micronucleus and a "somatic" macronucleus. After conjugation, chromosomes in the transcriptionally active macronucleus develop by fragmentation, elimination, and amplification of germ line chromosomes. Extensive chromosomal processing that generates a macronucleus with gene-sized fragments has thus far been well documented in members of only one class of ciliates, the Spirotrichea. Here we establish the broad distribution of extensive fragmentation among members of the class Phyllopharyngea and the genera Metopus (order Armophorida) and Nyctotherus (order Clevelandellida). Moreover, analyses of small-subunit rDNA genealogies indicate that gene-sized chromosomes occur in members of the three separate clades (1) the class Spirotrichea, (2) the class Phyllopharyngea, and (3) the two orders Clevelandellida and Armophorida. Together, these data indicate that the generation of gene-sized chromosomes is widespread and demonstrate multiple origins of extensive fragmentation within ciliates.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cilióforos
Límite:
Animals
Idioma:
En
Revista:
Mol Biol Evol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos