জিমনোস্পার্ম এর পুং ও স্ত্রী জননাঙ্গের গঠন

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Origin and Evolution in Sex of algae

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  Origin and Evolution in Sex of algae Sexual reproduction is characterised by the fusion of two similar or dissimilar cells. This is a sign of relatively advanced stage in evolution. Sex is not an obvious in the lower plants (like algae) as it is in higher plants. But in any way the study of reproductive processes of various classes of Algae throws considerable light on the origin and evolution of sex in the branch of plants like Algae.   Origin of Sex: Most primitive algae the cyanophyceae (Myxophyceae) reproduce only the method of asexual and vegetative reproduction. Sexual reproduction is entirely absent in their case. In forms like Nostoc and oscillatoria, it takes place by means of hormogones in which the plant body breaks up into group of few cells. In class xanthophyceae, chrysophyceae, cryptophyceae and dinopphyceae, sexuality is rare and has not much evolved beyond the stage of isogamy.   In higher classes of algae reproduction takes place by vegetative,...
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Chromodomain & Bromodomain

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Chromodomain & Bromodomain Chromodomain A chromodomain is a protein structural domain of about 40-50 amino acid residues commonly found in proteins associated with the remodeling and manipulation of chromatin. It is also known as chromatin organization modifier. It is first identified in Drosophila modifiers of variegation.   The chromodomains alter the structure of chromatin to the condensed morphology of heterochromatin, a cytologically visible condition where gene expression is repressed.The domain is highly conserved among both plants and animals.It is represented in a large number of proteins found in many genomes.Some chromodomain-containing genes have multiple alternative splicing isoforms that omit the chromodomain entirely.In mammals, chromodomain-containing proteins are responsible for aspects of gene regulation related to chromatin remodeling and formation of heterochromatin regions. Chromodomain-containing proteins also bind methylated histonesand appear in the ...
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