Pairing and recombination features during meiosis in Cebus paraguayanus (Primates: Platyrrhini).
BACKGROUND
Among neotropical Primates, the Cai monkey Cebus paraguayanus (CPA) presents long, conserved chromosome syntenies with the human karyotype (HSA) as well as numerous C+ blocks in different chromosome pairs.In this study, immunofluorescence (IF) against two proteins of the Synaptonemal Complex (SC), namely REC8 and SYCP1, two recombination protein markers (RPA and MLH1), and one protein involved in the pachytene checkpoint machinery (BRCA1) was performed in CPA spermatocytes in order to analyze chromosome meiotic behavior in detail.


RESULTS
Although in the vast majority of pachytene cells all autosomes were paired and synapsed, in a small number of nuclei the heterochromatic C-positive terminal region of bivalent 11 remained unpaired. The analysis of 75 CPA cells at pachytene revealed a mean of 43.22 MLH1 foci per nucleus and 1.07 MLH1 foci in each CPA bivalent 11, always positioned in the region homologous to HSA chromosome 21.


CONCLUSIONS
Our results suggest that C blocks undergo delayed pairing and synapsis, although they do not interfere with the general progress of pairing and synapsis.
Garcia-Cruz
Raquel
R
Unitat de Biologia Cellular i Genètica Mèdica, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain. raquel.garcia@uab.es
Robles
Pedro
P
Steinberg
Eliana R
ER
Camats
Nuria
N
Brieño
Miguel A
MA
Garcia-Caldés
Montserrat
M
Mudry
Marta D
MD
D000818:Animals; D002428:Cebus / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D023902:Chromosome Pairing; D002875:Chromosomes / Q000235:genetics; D006570:Heterochromatin / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008540:Meiosis; D011995:Recombination, Genetic; D013090:Spermatocytes / Q000378:metabolism
D018797:Cell Cycle Proteins; D006570:Heterochromatin