scholarly journals Molecular Analysis of Nondisjunction in Mice Heterozygous for a Robertsonian Translocation

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1219-1224
Author(s):  
Lara A Underkoffler ◽  
Laura E Mitchell ◽  
A Russell Localio ◽  
Shannon M Marchegiani ◽  
Justin Morabito ◽  
...  
Keyword(s):  
Molecular Analysis ◽  
Robertsonian Translocation ◽  
Metacentric Chromosome ◽  
Paternal Age ◽  
Chromosome 7 ◽  
Parental Origin ◽  
Molecular Genotyping ◽  
Factors Influencing ◽  
Meiotic Nondisjunction ◽  
Acrocentric Chromosomes

Abstract A Robertsonian translocation results in a metacentric chromosome produced by the fusion of two acrocentric chromosomes. Rb heterozygous mice frequently generate aneuploid gametes and embryos, providing a good model for studying meiotic nondisjunction. We intercrossed mice heterozygous for a (7.18) Robertsonian translocation and performed molecular genotyping of 1812 embryos from 364 litters with known parental origin, strain, and age. Nondisjunction events were scored and factors influencing the frequency of nondisjunction involving chromosomes 7 and 18 were examined. We concluded the following: The frequency of nondisjunction among 1784 embryos (3568 meioses) was 15.9%.Nondisjunction events were distributed nonrandomly among progeny. This was inferred from the distribution of the frequency of trisomics and uniparental disomics (UPDs) among all litters.There was no evidence to show an effect of maternal or paternal age on the frequency of nondisjunction.Strain background did not play an appreciable role in nondisjunction frequency.The frequency of nondisjunction for chromosome 18 was significantly higher than that for chromosome 7 in males.The frequency of nondisjunction for chromosome 7 was significantly higher in females than in males. These results show that molecular genotyping provides a valuable tool for understanding factors influencing meiotic nondisjunction in mammals.

Presence of an Additional Metacentric Chromosome in AKR/TIALD Leukaemic Cells

Nature ◽  
1970 ◽  
Vol 225 (5234) ◽  
pp. 737-738 ◽  
Author(s):  
E. LEGRAND ◽  
J. F. DUPLAN
Keyword(s):  
Metacentric Chromosome ◽  
Leukaemic Cells

scholarly journals The role of chromosomal fusion in the karyotypic evolution of the genus Ageneiosus (Siluriformes: Auchenipteridae)

2013 ◽  
Vol 11 (2) ◽  
pp. 327-334 ◽  
Author(s):  
Roberto Laridondo Lui ◽  
Daniel Rodrigues Blanco ◽  
Juliana de Fatima Martinez ◽  
Vladimir Pavan Margarido ◽  
Paulo Cesar Venere ◽  
...  
Keyword(s):  
Chromosome Pair ◽  
5S Rdna ◽  
Proximal Region ◽  
Terminal Region ◽  
Metacentric Chromosome ◽  
South American ◽  
Submetacentric Chromosome ◽  
Araguaia River ◽  
The Family ◽  
Preferential Location

Ageneiosus is the most widely distributed genus of the family Auchenipteridae among South American river basins. Although chromosome studies in the family are scarce, this genus has the largest number of analyzed species, with 2n = 54 to 56 chromosomes, differing from the rest of the family (2n = 58). This study aimed to analyze Ageneiosus inermis from the Araguaia River basin. The diploid number found was of 56 chromosomes. Heterochromatin was allocated in terminal region of most chromosomes, plus a pericentromeric heterochromatic block in pair 1, a pair distinguished by size in relation to other chromosomes pairs. AgNORs were detected in only one submetacentric chromosome pair, which was confirmed by FISH. 5S rDNA was present in only one metacentric chromosome pair. Hybridization with [TTAGGG]n sequence marked the telomeres of all chromosomes, in addition to an ITS in the proximal region of the short arm of pair 1. The repetitive [GATA]n sequence was dispersed, with preferential location in terminal region of the chromosomes. Ageneiosus has a genomic organization somewhat different when compared to other Auchenipteridae species. Evidences indicate that a chromosomal fusion originated the first metacentric chromosome pair in A. inermis, rearrangement which may be a basal event for the genus

scholarly journals An Extra Small Metacentric Chromosome in a Female Child

1966 ◽  
Vol 3 (4) ◽  
pp. 295-297 ◽  
Author(s):  
R. F. Tamburro ◽  
C. E. Johnson
Keyword(s):  
Female Child ◽  
Metacentric Chromosome

Bisatellited extra small metacentric chromosome in newborns

2008 ◽  
Vol 6 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Ursula Friedrich ◽  
Johannes Nielsen
Keyword(s):  
Metacentric Chromosome

scholarly journals A case of chromosome dissociation in a shrew

1973 ◽  
Vol 22 (3) ◽  
pp. 323-324 ◽  
Author(s):  
J. Olert
Keyword(s):  
Common Shrew ◽  
Normal Karyotype ◽  
Metacentric Chromosome

SUMMARYA male common shrew trapped at Bonn/BRD was found to have a karyotype differing from the normal karyotype by a dissociation of a large metacentric chromosome. Similar findings are hitherto unknown in mammals.

Physical localization and genetic mapping of the fertility restoration gene Rfo in canola (Brassica napus L.)

Genome ◽  
2009 ◽  
Vol 52 (4) ◽  
pp. 401-407 ◽  
Author(s):  
Jiuhuan Feng ◽  
Valerio Primomo ◽  
Zenglu Li ◽  
Yongping Zhang ◽  
Chao-Chien Jan ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Genetic Mapping ◽  
Average Length ◽  
Repeated Sequences ◽  
Metacentric Chromosome ◽  
45S Rdna ◽  
Metaphase Chromosomes ◽  
Brassica Napus L ◽  
Bac Clones ◽  
C Genome

The Ogu cytoplasm for male sterility and its fertility restorer gene Rfo in canola ( Brassica napus L.) were originally introgressed from radish ( Raphanus sativus L.) and have been widely used for canola hybrid production and breeding. The objective of this study was to determine the physical location of the Rfo locus in the canola genome using fluorescence in situ hybridization and genetic mapping. For physical localization of the Rfo gene, two bacterial artificial chromosome (BAC) clones, G62 and B420, which were closely linked to the Rfo gene, were used as probes to hybridize with the somatic metaphase chromosomes of a canola hybrid variety, PHI-46 (46H02), containing the Rfo fragment. The results showed that both clones were physically located at the end of one large metacentric chromosome. By simultaneous use of two BAC clones and 45S rDNA repeated sequences as the probes, we demonstrated that the large metacentric chromosome probed with the two BAC clones did not carry 45S rDNA repeated sequences. The chromosome was 3.65 ± 0.74 µm in average length (20 cells) and ranked second in size among the chromosomes without 45S rDNAs. The centromere index of the chromosome (20 cells) was calculated as 43.74 ± 4.19. A comparison with previously reported putative karyotypes of B. napus (AACC) and its diploid ancestors Brassica rapa L. (AA) and Brassica oleracea L. (CC) suggests that the chromosome carrying the Rfo fragment might belong to one of three large metacentric chromosomes of the C genome. Genetic mapping has confirmed the localization of the Rfo fragment to the distal region of linkage group N19, which corresponds to the C genome in B. napus. This study has provided the evidence of the location of the Rfo gene on canola chromosomes and established a basic framework for further physical mapping and manipulation of the gene.

Origin of a small metacentric chromosome: Familial and cytogenetic evidence

2008 ◽  
Vol 8 (5) ◽  
pp. 364-369 ◽  
Author(s):  
Kenneth M. Taylor ◽  
Howard L. Wolfinger ◽  
Michael G. Brown ◽  
David L. Chadwick
Keyword(s):  
Metacentric Chromosome ◽  
Cytogenetic Evidence
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