THREE NEW CHROMOSOMAL TRANSLOCATIONS IN HAWORTHIA

1968 ◽  
Vol 10 (3) ◽  
pp. 487-494 ◽  
Author(s):  
Herbert P. Riley ◽  
S. K. Majumdar
Keyword(s):  
Reciprocal Translocation ◽  
Acrocentric Chromosome ◽  
Centric Fusion ◽  
Metacentric Chromosome ◽  
Chromosomal Translocations ◽  
Short Chromosome ◽  
Acrocentric Chromosomes ◽  
Fusion Type

In one plant of a small-leaved form of Haworthia glauca a centric fusion type of reciprocal translocation was found between two long chromosomes with subterminal centromeres that interchanged to form a long metacentric and a short acrocentric chromosome; the latter is larger than the normal short chromosomes of the complement and consists of the short arms of the two original long chromosomes. In a typical plant of the same species a similar interchange was followed or accompanied by a second interchange between the short translocation chromosomes and a normal short chromosome to form a somewhat intermediate-sized acrocentric and a very short metacentric chromosome. In a plant of H. fulva a long and a short chromosome interchanged to produce two intermediate-sized acrocentric chromosomes. Possible evolutionary implications of these interchanges are discussed.

Centromere orientation at metaphase I of a translocation heterozygote in lentil

1983 ◽  
Vol 25 (6) ◽  
pp. 547-553 ◽  
Author(s):  
Frida Buruchin ◽  
G. Ladizinsky
Keyword(s):  
Reciprocal Translocation ◽  
Acrocentric Chromosome ◽  
Similar Length ◽  
Translocation Heterozygote ◽  
Ring Bivalents ◽  
Acrocentric Chromosomes ◽  
Number Of Cells ◽  
Metaphase I

Reciprocal translocation between submetacentric and acrocentric chromosomes of lentil was studied. This interchange did not entail karyotypic changes. Two homomorphic ring bivalents produced by the four chromosomes of the translocation complex indicated that the long arm of the acrocentric chromosome was involved in the interchange. Chiasmata distribution in the native arms, the translocated and interstitial segments in bivalents and quadrivalents, was taken as an indication for two pairing pattern in the translocation complex. Chiasma terminalization in the short arm of the acrocentric chromosome of the translocation complex was faster in bivalents than in quadrivalents. The overwhelming number of cells with alternate-1 compared with alternate-2 orientation was attributed to the similar length of the zigzag diagonals of alternate-1 that apparently induced greater stability. The necessary elements for adjacent-2 orientation were available in the examined material but were practically absent. Pole–centromere specificity was proposed for explaining the absence of adjacent-2 in the present and other studies and the orientation of homologous centromeres to opposite poles even when they were located in different bivalents.

scholarly journals Chromosome synapsis, recombination and epigenetic modification in rams heterozygous for metacentric chromosome 3 of the domestic sheep Ovis aries and acrocentric homologs of the argali Ovis ammon

2019 ◽  
Vol 23 (3) ◽  
pp. 355-361
Author(s):  
T. I. Bikchurina ◽  
E. K. Tomgorova ◽  
A. A. Torgasheva ◽  
V. A. Bagirov ◽  
N. A. Volkova ◽  
...  
Keyword(s):  
Epigenetic Modification ◽  
Centric Fusion ◽  
Domestic Animal ◽  
Ovis Aries ◽  
Metacentric Chromosome ◽  
Farm Animals ◽  
Chromosome 3 ◽  
Domestic Sheep ◽  
Acrocentric Chromosomes ◽  
Nonhomologous Synapsis

Hybridization of domestic animal breeds with their wild relatives is a promising method for increasing the genetic diversity of farm animals. Resource populations derived from the hybridization of various breeds of domestic sheep with mouflon and argali are an important source of breeding material. The karyotypes of argali and domestic sheep differ for a Robertsonian translocation, which occurred in the common ancestor of mouflon and domestic sheep (Ovis aries) due to the centric fusion of chromosomes 5 and 11 of the argali (O. ammon) into chromosome 3 of sheep. It is known that heterozygosity for translocation can lead to synapsis, recombination and chromosome segregation abnormalities in meiosis. Meiosis in the heterozygotes for translocation that distinguishes the karyotypes of sheep and argali has not yet been studied. We examined synapsis, recombination, and epigenetic modification of chromosomes involved in this rearrangement in heterozygous rams using immunolocalization of key proteins of meiosis. In the majority of cells, we observed complete synapsis between the sheep metacentric chromosome and two argali acrocentric chromosomes with the formation of a trivalent. In a small proportion of cells at the early pachytene stage we observed delayed synapsis in pericentromeric regions of the trivalent. Unpaired sites were subjected to epigenetic modification, namely histone H2A.X phosphorylation. However, by the end of the pachytene, these abnormalities had been completely eliminated. Asynapsis was replaced by a nonhomologous synapsis between the centromeric regions of the acrocentric chromosomes. By the end of the pachytene, the γH2A.X signal had been preserved only at the XY bivalent and was absent from the trivalent. The translocation trivalent did not differ from the normal bivalents of metacentric chromosomes for the number and distribution of recombination sites as well as for the degree of centromeric and crossover interference. Thus, we found that heterozygosity for the domestic sheep chromosome 3 and argali chromosomes 5 and 11 does not cause significant alterations in key processes of prophase I meiosis and, therefore, should not lead to a decrease in fertility of the offspring from interspecific sheep hybridization.

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.

scholarly journals Centromeric loss in translocations of centric fusion type in cattle and water buffalo

Hereditas ◽  
2008 ◽  
Vol 106 (1) ◽  
pp. 73-81 ◽  
Author(s):  
LEOPOLDO IANNUZZI ◽  
DINO DI BERARDINO ◽  
INGEMAR GUSTAVSSON ◽  
LINO FERRARA ◽  
GIULIA PIA DI MEO
Keyword(s):  
Water Buffalo ◽  
Centric Fusion ◽  
Fusion Type

Reciprocal translocation versus centric fusion between two No. 13 chromosomes

1973 ◽  
Vol 12 (4) ◽  
pp. 235-244 ◽  
Author(s):  
Lillian Y.F. Hsu ◽  
Hyon J. Kim ◽  
Eva Sujansky ◽  
B. Kousseff ◽  
K. Hirschhorn
Keyword(s):  
Reciprocal Translocation ◽  
Centric Fusion

Radioautographic identification of the D chromosomes involved in the centric fusion type of D/G translocation, t(DqGq)

1968 ◽  
Vol 32 (2) ◽  
pp. 191-193 ◽  
Author(s):  
A. DE CAPOA ◽  
W. R. BREG ◽  
T. KUSHNICK ◽  
O. J. MILLER
Keyword(s):  
Centric Fusion ◽  
Fusion Type

Analysis of synaptonemal complexes in two fertile heterozygous boars, both carriers of a reciprocal translocation involving an acrocentric chromosome

1989 ◽  
Vol 50 (4) ◽  
pp. 220-225 ◽  
Author(s):  
H. Jaafar ◽  
O. Gabriel-Robez ◽  
C. Ratomponirina ◽  
J. Boscher ◽  
M. Bonneau ◽  
...  
Keyword(s):  
Reciprocal Translocation ◽  
Acrocentric Chromosome ◽  
Synaptonemal Complexes

Pachytene analysis in a 17;21 reciprocal translocation carrier: role of the acrocentric chromosomes in male sterility

1987 ◽  
Vol 77 (3) ◽  
pp. 246-250 ◽  
Author(s):  
J. M. Luciani ◽  
M. R. Guichaoua ◽  
D. Delafontaine ◽  
M. O. North ◽  
O. Gabriel-Robez ◽  
...  
Keyword(s):  
Male Sterility ◽  
Reciprocal Translocation ◽  
Translocation Carrier ◽  
Acrocentric Chromosomes
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