Msh4 and Msh5 Function in SC-Independent Chiasma Formation During the Streamlined Meiosis ofTetrahymena

Abstract A single chromosome of the grass species Festuca pratensis has been introgressed into Lolium perenne to produce a diploid monosomic substitution line (2n = 2x = 14). The chromatin of F. pratensis and L. perenne can be distinguished by genomic in situ hybridization (GISH), and it is therefore possible to visualize the substituted F. pratensis chromosome in the L. perenne background and to study chiasma formation in a single marked bivalent. Recombination occurs freely in the F. pratensis/L. perenne bivalent, and chiasma frequency counts give a predicted map length for this bivalent of 76 cM. The substituted F. pratensis chromosome was also mapped with 104 EcoRI/Tru91 and HindIII/Tru91 amplified fragment length polymorphisms (AFLPs), generating a marker map of 81 cM. This map length is almost identical to the map length of 76 cM predicted from the chiasma frequency data. The work demonstrates a 1:1 correspondence between chiasma frequency and recombination and, in addition, the absence of chromatid interference across the Festuca and Lolium centromeres.

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Evidence of a joint control of chiasma formation in spermatocytes and oocytes of a grasshopper

Heredity ◽

10.1038/hdy.1990.112 ◽

1990 ◽

Vol 65 (3) ◽

pp. 419-422 ◽

Cited By ~ 4

Author(s):

J L Santos ◽

M I Cano

Keyword(s):

Chiasma Formation ◽

Joint Control

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Estimating meiotic chromosome pairing and recombination parameters in telocentric trisomics

Genome ◽

10.1139/g07-065 ◽

2007 ◽

Vol 50 (11) ◽

pp. 1014-1028 ◽

Cited By ~ 2

Author(s):

J. Sybenga ◽

H. Verhaar ◽

D.G.A. Botje

Keyword(s):

Gene Transfer ◽

Chromosome Pairing ◽

Genome Analysis ◽

Meiotic Chromosome ◽

Chiasma Formation ◽

Chromosome Morphology ◽

Test Material ◽

Gene Localization ◽

Maximum Information ◽

Chromosome 1R

Telocentric trisomics (telotrisomics; one arm of a metacentric chromosome present in addition to two complete genomes) are used in theoretical studies of pairing affinities and chiasma formation in competitive situations and applied in genome analysis, gene localization, gene transfer, and breakage of close linkages. These applications require knowledge of the recombination characteristics of telotrisomics. Appropriate cytological and molecular markers and favorable chromosome morphology are not always available or applicable for quantitative analyses. We developed new mathematical models for extracting the maximum information from simple metaphase I observations. Two types of telotrisomics of the short arm of chromosome 1R of rye ( Secale cereale ), including several genotypes, were used as test material. In simple telotrisomics, pairing between morphologically identical complete chromosomes was more frequent than pairing between the telocentric and either of the normal chromosomes. In the telocentric substitution, morphologically identical telocentrics paired less frequently with each other than either one with the normal chromosome. Pairing partner switch was significant. Interaction between the two arms was variable. Variation within plants was considerable. Telotrisomics without markers are suitable for analyzing pairing preferences, for gene localization and gene transfer, and for breaking tight linkages, but less so for genome analysis.

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