Presentation Detail

EvoDevo

Musser, Jacob [1], Gunter, GP [2], Prum, RO [3].

Investigating the Homology of Feathers and Scales with High-Throughput Genomics.

Feathers are an important anatomical innovation that evolvedin the ancestors of birds and facilitated the evolution of flight, greater thermoregulation,and other facets of modern avian life. However, the molecular basis for the evolution of feathers is poorly understood,and the homology of feathers to other skin derivatives, especially scales,remains contentious. Here, we take a newapproach to answering these questions by comparing transcriptomes fromdifferent stages of developing feathers, different avian and reptilian scales, and claws. We performed mRNA-seq ondifferent stages of skin appendage development collected from two distantly related birds, Chicken (Gallus gallus) and Emu (Dromaius novaehollandiae), and from American Alligator (Alligator mississippiensis), a member of the extant clade most closely related to birds. We found that in early development feathers and scutate scales, a broad asymmetric avian scale, share similar patterns of gene expression compared to other scales and claws. As development progresses, feathers turn offmuch of this shared gene expression and activate a large number of uniquegenes. This close relationship between feathers and scutate scales in early development, and subsequent unique expression in later feather development is supported independently by both epidermal and dermal transcriptomes, and by transcriptomes from developing feathers and scales of Emu, a distantly related avian species. Further, to complement our transcriptome data, we used immunohistochemistry to compare spatial patterns of expression and subcellular localization of the transcription cofactor β-catenin, the earliest known molecule expressed in feathers. Our preliminary evidence suggests β-catenin is expressed in similar spatial patterns in early developing feathers and scutate scales. These complementary results suggest feathers share similar molecular pathways to scutate scales in early development, and that feathers may have evolved via elaboration of an asymmetric scutate type scale.

1 - Yale University, Dept. of EEB, Peabody Museum of Natural History, Yale Systems Biology Institute, 21 Sachem St., ESC 158, New Haven, CT, 06520, USA
2 - Yale University, Dept. of EEB, Yale Systems Biology Institute, 137 Frontage Rd.,, Yale West Campus, ABC #271B, West Haven, CT, 06477, United States
3 - Yale University, Dept. of EEB, Yale Systems Biology Institute, 21 Sachem St., ESC 164, New Haven, CT, 06520, USA

Keywords:
evo-devo
Feathers
Homology
novelty.

Presentation Type: Regular Oral Presentation
Session: 31
Location: Rendezvous A/Snowbird Center
Date: Saturday, June 22nd, 2013
Time: 2:00 PM
Number: 31003
Abstract ID:1015
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation