Exam 21: Gene Structure and Development

Animal species exhibit an enormous diversity of genetic information contained in nuclear DNA. This may be reflected in very different genome sizes. One might predict that animals with more complex structures might show greater numbers of different types of mRNAs during development. Scientists investigating this possibility were surprised to find that similar numbers of genes were transcribed at a particular time in development among species whose genomes differed greatly in size. How can this result be interpreted?

Scientists have found that the lifetimes of mRNAs coding for pair- rule regulatory elements in Drosophila embryos may be measured in minutes. What does this suggest about the overall developmental plan of an animal body?

The protein of the bicoid gene in Drosophila determines

Suppose there was a mutation in the segment- polarity genes of Drosophila. What do you suppose might be the outcome?

Many different lineages of animals share similar pattern- formation gene complexes. The study of how these shared complexes function in evolution is termed

What types of changes in the regulation of development can lead to evolutionarily significant morphological changes?

Even though plant and animal development processes share a number of features, there are some differences between the two groups of organisms. Which of the following is NOT a shared characteristic of plant and animal development?

Cellular differentiation is usually produced by

Suppose you found several Drosophila mutants that possessed additional legs growing out of the head segments. The probable mutation would be found in

The Bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

Which of the following human cells contains the gene for alcohol dehydrogenase, a liver enzyme that processes alcohol?

Which of the following is not an example of the process of apoptosis during organ and tissue development?

What is common to gap genes, segment- polarity genes, and homeotic genes?

Undifferentiated cells that continue to proliferate throughout an individual's life are referred to by what terms in plants and animals respectively?

In combination, what do the products of gap genes, pair- rule genes, and segmentation polarity genes of fruit flies do?

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?

During development, what a cell differentiates into depends in part on its location along three body axes. Which axis runs towards the organism's belly?

Gene expression in developing organisms is regulated on several different levels. In many developing animals, regulation of gene expression is influenced by the action of Hox genes. Which of the following regulatory elements are produced by many Hox genes?

What does the term "genetic equivalence" refer to?