The behavior of nucleolus organizers in structurally changed karyotypes of barley

Autor: H. Nicoloff, G. Künzel, Rigomar Rieger, M. Anastassova-Kristeva
Rok vydání: 1977
Předmět:
Zdroj: Chromosoma. 62:103-109
ISSN: 1432-0886
0009-5915
DOI: 10.1007/bf00292632
Popis: Two standard karyotype barley lines and 18 lines with karyotypes reconstructed by means of induced reciprocal translocations have been studied with respect to nucleolus formation. The standard karyotype contains two pairs of satellite chromosomes (pairs 6 and 7). Five of the structurally changed karyotypes contain, as a result of reciprocal translocations between the standard satellite chromosomes, only one satellite chromosome pair, each chromosome with two satellites and two nucleolus organizing regions. Under these circumstances, only two of the four NORs are active in nucleolus formation while the other two — probably the transposed ones — remain inactive; hence the maximum number of primary nucleoli per nucleus is two. — When NORs are translocated to chromosomes with no NOR in the standard karyotyp, the normal pattern of nucleolus formation remains unchanged. The same is true after transposition of segments from other chromosomes to the satellites of the standard SAT-chromosome pairs 6 and 7. The results obtained are discussed with respect to effects of translocations on the activity and behaviour of nucleolus organizing regions.
Databáze: OpenAIRE
Externí odkaz: