IBIOMAR - CENPAT   25620
INSTITUTO DE BIOLOGIA DE ORGANISMOS MARINOS
Unidad Ejecutora - UE
artículos
Título:
The origin and evolutionary consequences of skeletal traits shaped by embryonic muscular activity, from basal theropods to modern birds.
Autor/es:
VARGAS, AO; RUIZ, M.; SOTO ACUÑA, S.; HAIDR, N.; ACOSTA HOSPITALECHE, C.; OSSA FUENTES, L; MUÑOZ, V.
Revista:
INTEGRATIVE AND COMPARATIVE BIOLOGY
Editorial:
OXFORD UNIV PRESS INC
Referencias:
Lugar: Oxford; Año: 2017
ISSN:
1540-7063
Resumen:
Embryonic muscular activity (EMA) is involved in the development of several distinctive traits of birds.Modern avian diversity and the fossil record of the dinosaur-bird transition allow special insight into their evolution.Traits shaped by EMA result from mechanical forces acting at post-morphogenetic stages, such that genes often play avery indirect role. Their origin seldom suggests direct selection for the trait, but a side-effect of other changes such as musculo-skeletal rearrangements, heterochrony in skeletal maturation, or increased incubation temperature (whichincreases EMA). EMA-shaped traits like sesamoids may be inconstant, highly conserved, or even disappear and thenreappear in evolution. Some sesamoids may become increasingly influenced by genetic-molecular mechanisms (geneticassimilation). There is also ample evidence of evolutionary transitions from sesamoids to bony eminences at tendoninsertion sites, and vice-versa. This can be explained by newfound similarities in the earliest development of both kindsof structures, which suggest these transitions are likely triggered by EMA. Other traits that require EMA for theirformation will not necessarily undergo genetic assimilation, but still be conserved over tens and hundreds of millionsof years, allowing evolutionary reduction and loss of other skeletal elements. Upon their origin, EMA-shaped traits maynot be directly genetic, nor immediately adaptive. Nevertheless, EMA can play a key role in evolutionary innovation, andhave consequences for the subsequent direction of evolutionary change. Its role may be more important and ubiquitous than currently suspected.