Unique expression patterns of multiple key genes associated with the evolution of mammalian flight.
Bats are the only mammals capable of true flight. Critical adaptations for flight include a pair of dramatically elongated hands with broad wing membranes. To study the molecular mechanisms of bat wing evolution, we perform genomewide mRNA sequencing and in situ hybridization for embryonic bat limbs. We identify seven key genes that display unique expression patterns in embryonic bat wings and feet, compared with mouse fore- and hindlimbs. The expression of all 5'HoxD genes (Hoxd9-13) and Tbx3, six known crucial transcription factors for limb and digit development, is extremely high and prolonged in the elongating wing area. The expression of Fam5c, a tumour suppressor, in bat limbs is bat-specific and significantly high in all short digit regions (the thumb and foot digits). These results suggest multiple genetic changes occurred independently during the evolution of bat wings to elongate the hand digits, promote membrane growth and keep other digits short. Our findings also indicate that the evolution of limb morphology depends on the complex integration of multiple gene regulatory networks and biological processes that control digit formation and identity, chondrogenesis, and interdigital regression or retention.
Institute of Molecular Ecology and Evolution (iAIR), East China Normal University, , Shanghai 200062, People's Republic of China, Division of Biological Sciences, University of California, , San Diego, CA 92093, USA, Department of Genetics, Harvard Medical School, , Boston, MA 02115, USA.
Zhe
Z
Wang
Mengyao
M
Dai
Yao
Y
Wang
Kimberly L
KL
Cooper
Tengteng
T
Zhu
Dong
D
Dong
Junpeng
J
Zhang
Shuyi
S
Zhang
D000818:Animals; D005075:Biological Evolution; D002685:Chiroptera / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D004622:Embryo, Mammalian / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D047108:Embryonic Development; D005426:Flight, Animal; D005786:Gene Expression Regulation; D055106:Genome-Wide Association Study; D017403:In Situ Hybridization; D051379:Mice; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014921:Wings, Animal / Q000033:anatomy & histology* / Q000196:embryology / Q000254:growth & development / Q000378:metabolism
D014157:Transcription Factors
5′HoxD; Fam5c; Tbx3; bat wing; mRNA-Seq