Provisional maps are presented for all acrocentric bivalents and bivalent 9, according to their chromomere patterns at pachytene in the human oocyte. Each G band is subdivided into several sub-bands whose numbers varies according to the degree of chromosomal compacting. Chromomere number and sequence are in basic agreement with those observed in late prophase mitotic chromosomes. Thus, metaphase G bands of mitotic chromosomes result from progressive compressing together of smaller chromomeres whose individuality disappears as chromosomal condensation increases with progression of prophase.
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Meiotic synapsis of homeologous chromosomes and mismatch repair protein detection in the parthenogenetic rock lizard Darevskia unisexualis.
Mol Reprod Dev
February 2021
Vavilov Institute of General Genetics RAS, Moscow, Russia.
Parthenogenetic species of Caucasian rock lizards of the genus Darevksia are important evidence for reticulate evolution and speciation by hybridization in vertebrates. Female-only lineages formed through interspecific hybridization have been discovered in many groups. Nevertheless, critical mechanisms of oogenesis and specifics of meiosis that provide long-term stability of parthenogenetic species are still unknown.
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J Assist Reprod Genet
January 2017
Genetics of Male Fertility Group. Unitat de Biologia Cel·lular. Departament de Biologia Cel·lular, Fisiologia i Immunologia. Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, (Cerdanyola del Vallès), 08193, Spain.
Purpose: The study aims to determine whether there is an altered bivalent positioning in metaphase I human spermatocytes from Robertsonian translocation carriers.
Methods: Metaphase I human spermatocytes from three 45,XY,der(13;14)(q10;q10) individuals and a 45,XY,der(14;15)(q10;q10) individual were analyzed. Proximity relationships of bivalents were established by analyzing meiotic preparations combining Leishman staining and multiplex-FISH procedures.
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Genetica
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INBIOMED-Instituto de Investigaciones Biomédicas, UBA, CONICET, Facultad de Medicina (UBA), Paraguay 2155, Piso 10, C1121ABG, Buenos Aires, Argentina.
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View Article and Find Full Text PDFHeterologous Synapsis and Crossover Suppression in Heterozygotes for a Pericentric Inversion in the Zebra Finch.
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INBIOMED (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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View Article and Find Full Text PDFSex-specific recombination maps for individual macrochromosomes in the Japanese quail (Coturnix japonica).
Chromosome Res
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INBIOMED (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 10, C1121ABG, Buenos Aires, Argentina.
Meiotic recombination in the Japanese quail was directly studied by immunolocalization of mutL homolog 1 (MLH1), a mismatch repair protein of mature recombination nodules. In total, 15,862 crossovers were scored along the autosomal synaptonemal complexes in 308 meiotic nuclei from males and females. Crossover frequencies calculated from MLH1 foci show wide similitude between males and females with slightly higher number of foci in females.
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