dnA sequence evolution in different parts of the
same developmental gene? Explain how.- in many organisms, such as insects and flower-
ing plants, morphological traits have been lost in
some species due to the evolution of develop-
mental arrest: growth and development cease,
eliminating the final trait. The remaining tissue
can be remodeled or resorbed for other use.
What does this observation suggest about the
nature of mutations and adaptive evolution in
these cases? - development of a morphological structure
involves many different types of genes and their
products, including transcription factors, signal-
ing proteins, and effectors such as enzymes.
When a morphological change occurs in a
single mutational step, which types of genes or
gene products might be more or less likely to
be involved? Within a gene, would such single-
step events be more likely to involve mutation to
protein-coding sequences or changes in regula-
tion? Why?- Almost all extant animals have Hox genes that
are involved in body patterning. What can we
infer about the common ancestors of living
animals based on the presence of these genes?
Why do organisms that are incredibly distinct
morphologically, with completely different
body plans, use so many of the same patterning
genes?
15_EVOL4E_CH15.indd 398 3/22/17 1:31 PM