How chromosome ends are replicated?

DNA replication is carried out by DNA polymerase. During the replication, one DNA strand synthesized as leading strand and the other as lagging strand. The leading strand synthesis is continuous, whereas lagging strand synthesis is discontinuous. DNA replication at the DNA ends i.e. telomeres is an altogether different story. If a primer forms at the [...]

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Maize Mini-chromosomes. Algae as Biofuel

This post is about two recent developments in the field of biotechnology and environmental science.
1) Agrobacterium-mediated transformation is the method of choice for inserting foreign genes into the plant genome. Through this method one gene could be introduced at a time in a single experiment. However, to introduce two foreign genes, one needs to develop [...]

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Centromere contd…

The sequence elements of Saccharomyces cerevisiae centromeres are not present in other eukaryotes; they are absent even in other yeast species. The DNA sequences of centromeres are highly diverse among eukaryotes. However, some similarities have been revealed in centromere consensus sequences among eukaryotes. The centromeres of multicellular eukaryotes are surrounded by highly repetitive DNA ; [...]

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Centromere

The constricted region on the chromosome where the two DNA molecules are attached is called the centromere. Much of the sequence information available on centromere is based on comparison of centromeric DNA sequences among the chromosomes of Saccharomyces cerevisiae or the budding yeast. Each of the yeast chromosome carries contains a conserved centromeric region called [...]

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Protecting the chromosome ends

This post is in continuation to the previous post Telomeres: The ends of the chromosome
Once telomeres have been added to the chromosome ends, different organisms use any of the three different methods to protect the ends of chromosomes.
1) The ends of telomeres which are guanine-rich form complex structures called the G-tetraplex. Four Gs form this planar [...]

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Telomeres: The ends of the chromosome

Telomeres define the chromsosome ends. The two criteria which identify a telomere are:
1) It must lie at the chromosome end.
2)  It must confer stability on a linear molecule.
Several telomeric sequences are known from various eukaryotic organisms. Each telomere consists of a long series of short, tandemly repeated sequences. The telomere construction follows a universal principle. [...]

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The Chromosome

The term chromosome was coined by W. Waldeyer in 1888. The word chromosome means “coloured body”. Chromosomes were discovered by C. von Nageli in 1842. Each chromosome is composed of proteins and nucleic acid (DNA). The proteins in case of higher organisms are histones. Thus chromosomes are nucleoprotein in nature. The nucleoprotein material of the [...]

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