In 1848, Hofmeister made an intriguing
discovery by observing filament or thread-like structures within the nuclei of
pollen mother cells in Tradescantia. Building upon this observation, the German
embryologist Walther Flemming, during his examination of rapidly dividing cells
in salamander larvae in 1882, also identified these threads. Later, in 1888,
these structures were officially termed "chromosomes" by Waldyer. The
name "chromosomes" originates from the Greek words "chrome"
meaning color and "soma" meaning body, reflecting their dark staining
characteristics. Chromosomes can be found in the cells of all eukaryotes.
In most cases, nuclear DNA is associated with
proteins, forming lengthy fibers known as chromatin. However, during cell
division, the chromatin undergoes condensation, transforming into distinct
chromosome structures. The number of chromosomes present varies across
different species, ranging from as few as two pairs in organisms like Mucor to
over 500 pairs in others.
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| Somatic chromosomes number of some organisms |
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