# MOLECULAR BASIS OF EVOLUTIONARY CHANGE IN DEVELOPMENT

> **NIH NIH R01** · TRUSTEES OF INDIANA UNIVERSITY · 1993 · $240,640

## Abstract

For evolution to occur, there must be modifications in developmental
process. However, the relationship between development and evolution is
only beginning to receive experimental investigation. The studies
proposed here experimentally address the nature of changes in gene
expression that underly dramatic shifts in timing and cell fate
determination that accompany replacement of typical larval development
by direct development in a sea urchin. The use of this system allows us
to test mechanisms of change in development at the level of cell lineage
determination and behavior at the level of gene activity. We are able to
directly examine the mechanistic underpinnings of one of the key
concepts in the evolution of development, that is heterochrony, or
changes in relative timing of developmental events.

The experimental system is a molecular and developmental comparison of a
direct developing sea urchin versus its dosest typical developing
species. We have already demonstrated that homologous cell lineages can
be identified, and we have observed heterochronies at the cellular and
molecular levels in these species. We also have begun tracing cell
lineages and cloning cell lineage-specific expressed genes. The major
questions to be studied include the following: Are cell fates modified
by autonomous determination or by modified patterns of induction? What
are the mechanisms for the observed heterochronies in the evolution of
direct development? How are gene expression programs changed in modified
cell lineages? How distant are typical and direct developing species,
and what are their precise phylogenetic relationships?

The study of the evolution of developmental processes adds a new and
potentially powerful means of understanding the underlying processes of
developing systems, because closely related organisms that differ in
specific developmental processes provide us with natural variants in
these processes. The details of process modification by which these
variants have come to differ provides a way of probing basic
developmental processes and their controls.

## Key facts

- **NIH application ID:** 2198220
- **Project number:** 5R01HD021337-08
- **Recipient organization:** TRUSTEES OF INDIANA UNIVERSITY
- **SAM.gov UEI:** YH86RTW2YVJ4
- **Principal Investigator:** RUDOLF A RAFF
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $240,640
- **Award type:** 5
- **Project period:** 1986-06-01 → 1995-01-09

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2198220

## Citation

> US National Institutes of Health, RePORTER application 2198220, MOLECULAR BASIS OF EVOLUTIONARY CHANGE IN DEVELOPMENT (5R01HD021337-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2198220. Licensed CC0.

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