Exam 13: Evolution and Development

Which of the following statements about paralogs is FALSE?

Regulatory ________ are DNA sequences that turn off the expression of particular genes.

________ occurs when paralogs diverge and they divide the work initially undertaken by the parental gene before duplication.

Although many human characteristics are neotenous compared to a chimpanzee, head growth is not. In the fetus of both species, brain and head growth start at approximately the same developmental stage and progress at the same rate. Soon after birth, chimpanzee brain and head growth stops. Human brain and head growth continues for several years after birth. Thus, relative to head growth, reproduction is occurring at a later stage. Assuming that chimpanzees represent the ancestral condition, explain what type of heterochrony humans have in brain development.

If paedomorphosis via neoteny involves the retention of juvenile traits in adults, what is responsible for paedomorphosis via progenesis?

What is a regulatory enhancer of a gene?

Which of the following is UNLIKELY to occur when a gene is duplicated?

Hox genes encode

Karl Ernst von Baer proposed that diagnostic traits for distinguishing species among vertebrates appear at the ________ stages of development.

The process shown in "D" in the figure is an example of which of the following?

Process "C" shown in the figure is an example of which of the following?

Which of the following gene transplant scenarios, discussed in the textbook, would provide valuable information about the action of homeotic genes?

According to the phylogeny in the figure, which of the following statements is true?

Gene duplication can occur for both protein-coding and regulatory regions of genes. In the figure below, imagine that the yellow gene and both enhancer regions in B are duplicated. Propose a mechanism for how subfunctionalization might occur.

Which of the following scientists hypothesized that the developmental stages of an individual paralleled the evolutionary history of the species to which it belonged?

Parallelism in development

Which of the following cell types would you expect to be totipotent?

Crabs have claws on their front legs and many sets of walking legs (which lack claws) on segments posterior to the claws. Crabs can regenerate legs if they are lost. A walking leg was removed and tissue from the claw was transplanted onto the stump. If homeobox genes are responsible for the differentiation of leg types, what would you predict would happen to the stump? Describe analogous experiments that have been performed in other species.

How can natural selection lead to the loss of a gene following duplication?

By transferring neural crest cells from a duck to a quail and vice versa, Richard Schneider and Jill Helms (2003) demonstrated that