Distance segregation of sex chromosomes in crane-fly spermatocytes studied using laser microbeam irradiations.
Protoplasma
; 250(5): 1045-55, 2013 Oct.
Article
en En
| MEDLINE
| ID: mdl-23315093
ABSTRACT
Univalent sex chromosomes in crane-fly spermatocytes have kinetochore spindle fibres to each spindle pole (amphitelic orientation) from metaphase throughout anaphase. The univalents segregate in anaphase only after the autosomes approach the poles. As each univalent moves in anaphase, one spindle fibre shortens and the other spindle fibre elongates. To test whether the directionality of force production is fixed at anaphase, that is, whether one spindle fibre can only elongate and the other only shorten, we cut univalents in half with a laser microbeam, to create two chromatids. In both sex-chromosome metaphase and sex-chromosome anaphase, the two chromatids that were formed moved to opposite poles (to the poles to which their fibre was attached) at speeds about the same as autosomes, much faster than the usual speeds of univalent movements. Since the chromatids moved to the pole to which they were attached, independent of the direction to which the univalent as a whole was moving, the spindle fibre that normally elongates in anaphase still is able to shorten and produce force towards the pole when allowed (or caused) to do so.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cromosomas Sexuales
/
Espermatocitos
/
Segregación Cromosómica
/
Dípteros
Límite:
Animals
Idioma:
En
Revista:
Protoplasma
Asunto de la revista:
BIOLOGIA
Año:
2013
Tipo del documento:
Article