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For nearly 20 years, researchers have gathered together at the MBL to study the acorn worm. Saccoglossus kowalevskii is a hemichordate and often considered an evolutionary link between the vertebrate and invertebrate lineages. By studying the acorn worm, researchers at the 91�鶹���� have revealed multiple conserved genetic pathways that regulate vertebrate brain development, illuminating the evolution of nervous systems as well as the evolution of genetic regulation (what turns genes on and off).

Cool facts

• One particular species may reach a length of 2.5 meters (8 ft 2 in), although most acorn worms are much smaller.
• They are most closely related to the Echinoderms (sea stars, urchins, sea cumbers).
• There are 111 different species of acorn worm.

(ID Card Photo Credit: Ariel Pani)

Select Publications

Gillis JA, Fritzenwanker JH, Lowe CJ. A stem-deuterostome origin of the vertebrate pharyngeal transcriptional network. Proc Biol Sci. 2012 Jan 22;279(1727):237-46.

Lowe CJ, Wu M, Salic A, Evans L, Lander E, Stange-Thomann N, Gruber CE, Gerhart J, Kirschner M. Anteroposterior patterning in hemichordates and the origins of the chordate nervous system. Cell. 2003 Jun 27;113(7):853-65.

Pani, A., Mullarkey, E., Aronowicz, J. et al. Ancient deuterostome origins of vertebrate brain signalling centres. Nature 483, 289–294 (2012).

J. Aronowicz, C. J. Lowe, Hox gene expression in the hemichordate Saccoglossus kowalevskii and the evolution of deuterostome nervous systems, Integrative and Comparative Biology, Volume 46, Issue 6, December 2006, Pages 890–901,

Division: Deuterostome

Deuterostomia may not sound familiar, but it should: you are a deuterostome! Most deuterostomes belong to one of two groups that include most of its members—echinoderms, which includes animals such as the spiny-skinned starfish, sea urchins, and their relatives, and chordates, which include fish and other vertebrates (including humans). Learn more about the Deuterostome Division here.

Meet the Other Deuterostome Organisms

• • Axolotl (Ambystoma mexicanum)
  • Sea Squirt (Ciona intestinalis)
  • Western Clawed Frog (Xenopus tropicalis)

What is MBL March Madness?

Based on the March Madness NCAA basketball tournament, during MBL March Madness, popular MBL organisms face off for your votes. YOU have the opportunity to decide what organism is crowned victorious by voting for your favorite organisms in a series of head-to-head match-ups. Voting will take place on the 91�鶹���� social media channels from March 29 - April 7. Learn more and download a bracket at mbl.edu/march-madness.