Every life form changes through the ages, and evolution is the only constant. Except for horseshoe crabs \u2013 which have stayed the same for 450 million years, keeping everything from the eyes on their tail to the antibacterial cells in their blood.<\/p>\n
How they’ve managed to stay the same is a great mystery. Now, researchers at UConn\u2019s Institute for Systems Genomics are assembling a detailed map of the horseshoe crab\u2019s DNA. They hope the map will lead them to answers to the crabs\u2019 two great secrets: how their blood reacts to bacteria, and why the crabs seem frozen in time.<\/p>\n
Geneticist Rachel O\u2019Neill, director of the Institute, is intrigued by horseshoe crabs (the native Connecticut species is Limulus polyphemus<\/i>) because they\u2019re just so weird. They\u2019re members of Arthropoda, that vast phylum of life that includes insects, crustaceans, and spiders. But most of their relatives went extinct long, long ago, and horseshoe crabs\u2019 closest living relatives are ticks, spiders, and scorpions.<\/p>\n
There aren\u2019t many detailed DNA maps of spiders or ticks to compare horseshoe crabs to. And even if there were, horseshoe crabs aren\u2019t exactly normal spiders. A map of their DNA is a window into the DNA of the Ordovician period of the Paleozoic, a time long before the dinosaurs, when mollusks and trilobites dominated the seas and the most complex lifeforms on land were plants similar to liverworts.<\/p>\n
But even that long ago, bacteria were everywhere. And they were no friends to Limulus polyphemus<\/i>. The crabs\u2019 blood contains roaming cells called amoebocytes that attack bacteria and coagulate like glue around them, instantly sealing off holes in the circulatory system.<\/p>\n
That violent reaction to bacteria has made the horseshoe crab\u2019s blood extraordinarily valuable to the pharmaceutical and medical device industries, which use an extract from the blood to test for contamination every batch of vaccine, saline, or other injected drug, as well as every pacemaker, artificial hip, or other implanted device. Horseshoe crabs have to be captured and bled to provide the substance, and their declining numbers suggest the harvest is slowly killing them off.<\/p>\n
Although there is a synthetic replacement available, it has been slow to catch on. O’Neill and her students think there is potential to expand its use, and perhaps design other, related proteins that detect other types of contaminants, not just bacteria.<\/p>\n
\u201cAt this point it\u2019s science fiction. But this is a novel way of thinking about any contaminant detection,\u201d O\u2019Neill says.<\/p>\n
Graduate student Kate Castellano has raised the baby horseshoe crabs to watch how they grew from embryos to the inch-long three-year-olds shown in the video. Part of it was to understand their basic biology \u2013 no one had even published a guide to the care and feeding of horseshoe crab embryos before \u2013 and part of it is public education. The little Limulus<\/em> babies live in a 30-gallon tank in the common area of the Institute for Systems Genomics, and anyone can sit at the nearby table and watch them.\u00a0<\/span><\/p>\n \u201cThe dinosaurs came and went, but the crabs stayed the same,\u201d O\u2019Neill says. \u201cWe\u2019re exploring this fossil genome to understand the adaptations that let horseshoe crabs succeed for so long.\u201d<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" How they’ve managed to stay the same is a great mystery. Now, researchers at UConn are assembling a detailed map of the horseshoe crab\u2019s DNA, to learn why these ‘living fossils’ seem frozen in time.<\/p>\n","protected":false},"author":79,"featured_media":146725,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"video","meta":{"_acf_changed":false,"_crdt_document":"","wds_primary_category":0,"wds_primary_series":0,"wds_primary_attribution":0,"footnotes":""},"categories":[2226,2076,2225,70],"tags":[],"magazine-issues":[],"coauthors":[1899,1927],"class_list":["post-145632","post","type-post","status-publish","format-video","has-post-thumbnail","hentry","category-clas","category-research","category-uconn-storrs","category-video","post_format-post-format-video"],"pp_statuses_selecting_workflow":false,"pp_workflow_action":"current","pp_status_selection":"publish","acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-05-10 09:41:05","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/posts\/145632","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/users\/79"}],"replies":[{"embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/comments?post=145632"}],"version-history":[{"count":12,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/posts\/145632\/revisions"}],"predecessor-version":[{"id":146738,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/posts\/145632\/revisions\/146738"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/media\/146725"}],"wp:attachment":[{"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/media?parent=145632"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/categories?post=145632"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/tags?post=145632"},{"taxonomy":"magazine-issue","embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/magazine-issues?post=145632"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/today.uconn.edu\/wp-rest\/wp\/v2\/coauthors?post=145632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}