many genetic disorders or possible abnormalities that may occur in the future generations can be predicted through analyzing the features of the chromosomes. for this purpose, karyotype is often used which to make it, there is necessary to identify each one of the 24 chromosomes from the microscopic images. the first step of this process is to define the morphological and band pattern based fea...

Caryological studies were carried out on ten species of the genus Suaeda belonging to 27 samples of different populations in Iran. Important chromosome features including numbers, lengths, centromere locations and caryotypes were studied. All the species have basic chromosome numbers of x=9. Chromosome counts of S. acuminata (C.A.Mey.) Moq. (2n=18), S. aegyptiaca (Hasselq.) Zoh., (2n=l8)...

The centromere of chromosomes 1, 6 and 9 are physically mapped by the hypoploids of the six most proximal B-A translocations. The hypoploids are deficient for a paternal chromosome arm and, as a result, lose the paternal signal of those RFLP markers located on the missing chromosome arm. Of those markers missing from the hypoploids, the two most proximal ones on each arm of a chromosome define ...

The ability of centromeres to alternate between active and inactive states indicates significant epigenetic aspects controlling centromere assembly and function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In such derivatives o...

In Saccharomyces cerevisiae, a reciprocal translocation between chromosome II and a linear plasmid carrying a centromere (CEN6) has split chromosome II into two fragments: one, approximately 530 kilobase pairs (kbp) in size, has the left arm and part of the right arm of chromosome II; the other, a telocentric fragment approximately 350 kbp in size, has CEN6 and the rest of the right arm of chro...

The centromere region of Saccharomyces cerevisiae chromosome III has been replaced by various DNA fragments from the centromere regions of yeast chromosomes III and XI. A 289-base pair centromere (CEN3) sequence can stabilize yeast chromosome III through mitosis and meiosis. The orientation of the centromeric fragments within chromosome III has no effect on the normal mitotic or meiotic behavio...

During meiosis, homologous chromosomes pair and then segregate from each other at the first meiotic division. Homologous centromeres appear to be aligned when chromosomes are paired. The role of centromere alignment in meiotic chromosome segregation was investigated in Saccharomyces cerevisiae diploids that contained one intact copy of chromosome I and one copy bisected into two functional cent...

Assembly of kinetochore complexes, involving greater than one hundred proteins, is essential for chromosome segregation and genome stability. Neocentromeres, or new centromeres, occur when kinetochores assemble de novo, at DNA loci not previously associated with kinetochore proteins, and they restore chromosome segregation to chromosomes lacking a functional centromere. Neocentromeres have been...

Experiments designed to characterize the association between disomic chromosome loss and centromere-adjacent mitotic recombination were performed. Mitotic gene convertants were selected at two heteroallelic sites on the left arm of disomic chromosome III and tested for coincident chromosome loss. The principal results are: (1) Disomic chromosome loss is markedly enhanced (nearly 40-fold) over b...

Meiotic chromosome segregation involves pairing and segregation of homologous chromosomes in the first division and segregation of sister chromatids in the second division. Although it is known that the centromere and kinetochore are responsible for chromosome movement in meiosis as in mitosis, potential specialized meiotic functions are being uncovered. Centromere pairing early in meiosis I, e...