Paracentric inversion involving a NOR-bearing chromosome of rainbow trout (Oncorhyncus mykiss): electron microscopy studies of the synaptonemal complex
作者:
期刊:
Caryologia
(Taylor Available online 1996)
卷期:
Volume 49,
issue 3-4
页码: 335-342
ISSN:0008-7114
年代: 1996
DOI:10.1080/00087114.1996.10797378
出版商: Taylor & Francis
关键词: NORs;paracentric inversion;meiosis;synaptonemal complex;rainbow trout
数据来源: Taylor
摘要:
Cytogenetic studies conduced on a sample of 19 specimens of rainbow trout(Oncorhyncus mykiss)showed that 6 presented two chromosomes with a single subterminal AgNOR on the short arms and 13 presented one chromosome with a single subterminal Ag-NOR and a second chromosome with two small subterminal Ag-NORs. Synaptonemal complex studies showed the presence of a pairing failure involving the two lateral elements (LEs) of the NOR-bearing chromosomes only in those specimens with two different NOR-bearing chromosomes, suggesting that the chromosomes with two Ag-NORs originated from a paracentric inversion involving a terminal segment of the original NOR-bearing chromosome. A comparative analysis between three normal and three heterozygous fishes suggest that in the latter group the LEs of the NOR-bearing chromosomes initiate the synaptic process in a more delayed manner, the synapsis develops more quickly, and the nucleolus stays associated with chromosomes for a longer time.
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