How are Human Hands and Fish Fins Linked?

Vocabulary: gene, HOX gene, pectoral fin, evolutionary descent, developmental mechanisms, CRISPR

NGSS: LS4.A: Evidence of Common Ancestry and Diversity, ETS2.A: Interdependence of Science, Engineering, and Technology, CC1: Patterns, can be used to build toward HS-LS4–1.

Common Core State Standards: CCSS.ELA-LITERACY.RI.6.1, CCSS.ELA-LITERACY.RI.7.1, CCSS.ELA-LITERACY.RI.8.1, CCSS.ELA-LITERACY.RI.9–10.1, CCSS.ELA-LITERACY.RI.11–12.1

A female specimen of a zebrafish. By Azul (Own work) [Copyrighted free use], via Wikimedia Commons

Until recently, scientists thought human hands had little in common with the long, thin, delicate bones in fish fins, even though the human arm evolved from something like those pectoral fins. Yet new research looking at zebrafish and a non-human mammal — the mouse — seems to have found a connection: a gene that, when mutated, leads to a mouse limb with no fingers and a zebrafish fin with significantly altered bones.

Kim Cooper, a developmental and cell biologist at the University of California-San Diego, describes how the human hand and fish fin could be linked, and what this connection might tell us about how our hands evolved.

Audio Excerpt “A Hand, a Fin, a Gene” Aug. 26, 2016. (Original Segment)

Print this segment transcript.

Questions

  • Compare and contrast the structures and bones in a human hand, bat wing, cat leg, and whale flipper (Christopher Auyeung; Source: CK-12 Foundation; License: CC BY-NC 3.0) with the pectoral fin bones of these fish fossils.
  • Describe the relationship between the fish fin and the mouse paw that the Shubin Lab research supported.
  • Explain how scientists in the Shubin Lab were able to determine a relationship between a fish fin and a mouse paw.
  • Kim Cooper discusses the regulatory sequence for the HOX gene. Based on the research, what effect does the regulatory sequence have on behavior of the gene?

Activity Suggestions

  • Use what you know about Kim Cooper’s research to talk about how scientists use disruptions in protein synthesis to test the functionality of different genes. Check out this video primer on evolutionary developmental biology.
  • Use the “A Hand, a Fin, a Gene” segment as a springboard for a discussion on the impact of advances in genetics on the study of evolutionary biology.

[Check out Jump In Jerboas to learn about another incredible animal appendage.]