How do the egl-1 and pos-1 phenotypes interact? Do you think this is a meaningful genetic interaction? Why?

What are the roles of cellular proto-oncogenes, and how are these roles consistent with their implication in oncogenesis?

The cystic fibrosis gene encodes a chloride channel protein necessary for normal cellular functions. Let us assume that if at least 5% normal channels are present, the affected individual has mild symptoms of cystic fibrosis. Having less than 5% normal channels produces severe symptoms. At least 50% of the channels must be expressed for the individual to be phenotypically normal. This gene has various mutant recessive alleles: Predict the percent of functional channels and severity of symptoms for the following genotypes: a. heterozygous for CF100 b. homozygous for CF100 c. heterozygous, with one copy of CF100 and one of CF3 d. heterozygous, with one copy of CF1 and one copy of CF3

What percentage of the DNA in the genome actually corresponds to genes? How much is actually protein-coding exons? What makes up the rest?

A region on chromosome 6 has been linked to schizophrenia, but researchers have not found a specific gene associated with this disease. What steps would be necessary to locate the gene?

Almost all calico cats (one is pictured in FIGURE 10.7B) are female. Why? B When this calico cat was an embryo, one of the two X chromosomes was inactivated in each of her cells. The descendants of the cells formed her adult body, which is a mosaic for expression of X chromosome genes. Black fur arises in patches where genes on the X chromosome inherited from one parent are expressed; orange fur arises in patches where genes on the X chromosome inherited from the other parent are expressed. FIGURE 10.7 Animated X chromosome inactivation.

Fragile-X syndrome causes the most common form of inherited intellectual disability. What is the chromosomal abnormality associated with this disorder? What is the phenotype of this disorder?

When the human genome sequence was finally completed, scientists were surprised to discover that the genome contains far fewer genes than expected. How many genes are present in the human genome? Scientists have also found that there are many more different kinds of proteins in human cells than there are different genes in the genome. How can this be explained?

A geneticist discovers that a girl with Down syndrome has a Robertsonian translocation involving chromosomes 14 and 21. If she has an older brother who is phenotypically normal, what are the chances that he is a translocation carrier?

Who Owns Your Genome? John Moore, an engineer working on the Alaska oil pipeline, was diagnosed in the mid-1970s with a rare and fatal form of cancer known as hairy cell leukemia. This disease causes overproduction of one type of white blood cell known as a T lymphocyte. Moore went to the UCLA Medical Center for treatment and was examined by Dr. David Golde, who recommended that Moores spleen be removed in an attempt to slow down or stop the cancer. For the next 8 years, John Moore returned to UCLA for checkups. Unknown to Moore, Dr. Golde and his research assistant applied for and received a patent on a cell line and products of that cell line derived from Moores spleen. The cell line, named Mo, produced a protein that stimulates the growth of two types of blood cells that are important in identifying and killing cancer cells. Arrangements were made with Genetics Institute, a small start-up company, and then Sandoz Pharmaceuticals, to develop the cell line and produce the growth-stimulating protein. Moore found out about the cell line and its related patents and filed suit to claim ownership of his cells and asked for a share of the profits derived from the sale of the cells or products from the cells. Eventually, the case went through three courts, and in July 1990n years after the case beganthe California Supreme Court ruled that patients such as John Moore do not have property rights over any cells or tissues removed from their bodies that are used later to develop drugs or other commercial products. This case was the first in the nation to establish a legal precedent for the commercial development and use of human tissue. The National Organ Transplant Act of 1984 prevents the sale of human organs. Current laws allow the sale of human tissues and cells but do not define ownership interests of donors. Questions originally raised in the Moore case remain largely unresolved in laws and public policy. These questions are being raised in many other cases as well. Who owns fetal and adult stem-cell lines established from donors, and who has ownership of and a commercial interest in diagnostic tests developed through cell and tissue donations by affected individuals? Who benefits from new genetic technologies based on molecules, cells, or tissues contributed by patients? Are these financial, medical, and ethical benefits being distributed fairly? What can be done to ensure that risks and benefits are distributed in an equitable manner? Gaps between technology, laws, and public policy developed with the advent of recombinant DNA technology in the 1970s, and in the intervening decades, those gaps have not been closed. These controversies are likely to continue as new developments in technology continue to outpace social consensus about their use. Should the physicians at UCLA have told Mr. Moore that his cells and its products were being commercially developed?