====== Genome size ======

The size of the genome (the amount of DNA in an organism's genes) varies enormously from one species to another. The smallest sizes, for viruses, ranges from around 2 thousand base-pairs to over a million.

Humans have about 3 billion (forming around 19,000 genes *) - but some plants have more than //50 times as many.// The New Caledonian fork fern (//Tmesipteris oblanceolate//), for example, has 160 billion. ([[https://www.cell.com/iscience/fulltext/S2589-0042(24)01111-8|ref.]])

The lack of correlation between the apparent complexity of an organism and its genome size is called the [[https://en.wikipedia.org/wiki/G-value_paradox|G-value paradox]]

There is currently no explanation for the wild variations in genome size.

>These variations have not yet been successfully explained, but may have a relation to the age of the species - i.e. older species tend to have more."\\ \\ Source : [[https://en.wikipedia.org/wiki/Genome#Genome_size|Wikipedia]].

//" Note:// Many organisms have large percentages of DNA (in some cases //up to 98%) //which //appears// to be redundant - and has been termed 'Junk DNA'. Its function (or non-function as the name suggests) is currently unclear.  See [[https://en.wikipedia.org/wiki/Noncoding_DNA#Junk_DNA|Wikipedia]] :

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 Also see: [[content:life_sciences:genetics:dna_rna|DNA / RNA]]