A) There are more copies of genes, meaning speciation had occurred by polyploidy.
B) The original gene copy is the outgroup, and the new gene copies are the adaptive
radiation.
C) Without duplicated genes, species would be vulnerable to extinction.
D) One copy of a gene can perform the original function, while other copies are
available to take on new functions.
Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two
molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid
change, the mutant hemoglobin tetramers associate with each other and assemble into
large fibers. Based on this information alone, we can conclude that sickle-cell
hemoglobin exhibits _____.
A) only altered primary structure
B) only altered tertiary structure
C) only altered quaternary structure
D) altered primary structure and altered quaternary structure; the secondary and tertiary
structures may or may not be altered
A lizard’s bobbing dewlap (a colorful flap of skin hanging from an Anolis lizard’s
throat) is an example of a(n) _____.