|Sizing up Spider Genomes|
October 31, 2003
Scientists have now measured the genome sizes of some 115 spider species, from ghost spiders to cobweb weavers to jumping spiders. Despite their abundance and diversityŚthere are more than 37,000 known species of spiders worldwideŚlittle has been known about their genomic make-up.
So far, it appears that jumping spiders have the largest genomes. With their big eyes and engaging behavior, they are considered the teddy bears of the spider world. Jumping spiders prey on flies. They are also characterized by a "jerky" way of moving around. In fact, they look like they are hopping every time they move.
Some of the smallest spider genomes are found in the orbweaver family. Orbweavers, also called stretch spiders, build their webs at an angle instead of straight up and down.
Comparative studies of spider genomes could provide clues why some spiders build webs and others don't. Genome studies may also help answer questions about spider longevitywhy some spider species may survive for 20 years and others live only one year.
The sizes of all the spider genomes are stored in an online database. The Animal Genome Size Database includes organisms from insects to spiders to earthworms and includes the genome sizes of more than 3,000 animals.
The database can be accessed here.
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