An irregular hourglass pattern describes the tempo of phenotypic development in placental mammal evolution.

ABSTRACT: Organismal development is defined by progressive transformations that ultimately give rise to distinct tissues and organs. Thus, temporal shifts in ontogeny often reflect key phenotypic differences in phylogeny. Classical theory predicts that interspecific morphological divergence originates towards the end of embryonic or fetal life stages, i.e. the early conservation model. By contrast, the hourglass model predicts interspecific variation early and late in prenatal ontogeny, though with a phylogenetically similar mid-developmental period. This phylotypic period, however, remains challenging to define within large clades such as mammals. Thus, molecular and morphological tests on a mammalian hourglass have not been entirely congruent. Here, we report an hourglass-like pattern for mammalia

SUBMITTER: Cordero GA 

PROVIDER: S-EPMC7280037 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature