Evolutionary theory has until recently stressed genetic mutations that alter protein amino acid sequences as the major source of variation that leads to speciation.Evo-devo (evolutionary developmental biology)offers a different understanding of the role of genetic change in evolution.Which of the following statements best summarizes this understanding?
A)Genetic mutations are not as important in evolutionary change as the environment in which the organism develops.
B)Changes in cell-cell interactions in a parent's body can lead to phenotypic change in offspring.
C)Similar genes are found in most developing animal bodies;changes in the times and places they are expressed can lead to phenotypic variation.
D)Greater numbers of genes,rather than the ways in which they are regulated,lead to the development of more complex animals over time.

Question

Quizplus · Accepted Answer

The evo-devo perspective emphasizes changes in gene expression, rather than changes in the protein coding sequences, as the key to evolutionary change. Similar genes are found in most developing animal bodies, but changes in the timing and location of their expression can lead to phenotypic variation. This is the essence of the "hourglass model" of embryonic development, which postulates that the middle stages of development are the most conserved across species, while the early and late stages are more variable. Evo-devo also emphasizes the role of cell-cell interactions and signaling pathways in shaping the developing organism.

Evolutionary Theory Has Until Recently Stressed Genetic Mutations That Alter