Comparative Hox genes expression within the dimorphic annelid Streblospio benedicti reveals patterning variation...

Area of Science:

• Developmental biology
• Evolutionary genetics
• Marine biology

Background:

• Hox genes establish anterior-posterior positional identity in Metazoans.
• Hox gene conservation across species highlights evolutionary relationships.
• Hox gene evolution can drive morphological novelty and body plan modifications.

Purpose of the Study:

• To compare Hox gene expression patterns during ontogeny in two distinct larval types of the marine annelid Streblospio benedicti.
• To investigate how spatial or temporal differences in Hox gene expression correlate with divergent morphology and life-history traits within a single species.

Main Methods:

• Utilized hybridization chain reaction (HCR) probes for in situ hybridization.
• Employed RNA sequencing (RNA-seq) to analyze gene expression.
• Compared Hox gene expression across ontogeny for two distinct larval morphotypes.

Main Results:

• Hox gene expression patterning was largely similar between the two larval types at equivalent developmental stages.
• Identified specific Hox genes exhibiting spatial or temporal expression differences between the larval types.
• These expression differences are associated with the observed morphological and life-history variations.

Conclusions:

• This study provides the first comparison of developmental divergence in Hox gene expression within a single species.
• Demonstrates that subtle changes in Hox gene expression can underlie significant body plan differences in larval evolution.
• Highlights the role of developmental plasticity in Hox gene regulation for generating evolutionary novelty.