Journal
SCIENCE
Volume 306, Issue 5697, Pages 828-833Publisher
AMER ASSOC ADVANCEMENT SCIENCE
DOI: 10.1126/science.1103707
Keywords
-
Categories
Ask authors/readers for more resources
Because of its simplicity, the binary-switch nature. of left-right asymmetry permits meaningful comparisons among many different organisms. Phylogenetic analyses of asymmetry variation, inheritance, and molecular. mechanisms reveal unexpected insights into how development evolves. First, directional asymmetry, an evolutionary novelty, arose from nonheritabie origins almost as often as from mutations, implying that genetic assimilation (phenotype precedes genotype) is a common mode of evolution. Second, the molecular pathway directing hearts leftward-the nodal cascade-varies considerably among vertebrates (homology of form does not require homology of development) and was possibly co-opted from a preexisting asymmetrical chordate organ system. Finally, declining frequencies of spontaneous asymmetry reversal throughout vertebrate evolution suggest that heart development has become more canalized.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available