Science 10Unit III: Genetics

Genetic Research

Genetics research is continually changing and developing in response to new discoveries. Scientists want to learn about sequences of genes that are associated with certain inherited traits as well as how those genes play a role.

Human Genome ProjectCompleted in 2003 after 13 years of study, scientists determined, base by base, the DNA sequence of the human genome. Goals of the Human Genome Project included identifying all of the human genes and making them available for study. Identifying the genome sequences of humans and many other organisms allows for a much more comprehensive understanding of biological systems that researchers can apply in human health, agriculture, and the environment.

Surprising Discoveries• Only about 2 percent of the nucleotides in the human genome make up our genes and code for all the proteins in the body.• The estimated 25 000 total number of genes is much less than scientists predicted. Previous

estimates were between 80 000 and 140 000.• Over 50 percent of our DNA consists of stretches of repeating sequences.• There is very little genetic variation within our species. About 99.9 percent of the DNA sequence is almost exactly the same in all people.

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Science 10Unit III: Genetics

Genomics

Genomics is the study of genomes and how genes work together to control phenotype. Although some traits are determined by only one gene, most traits involve multiple genes. Human Genome Project allows us to consider multiple genes and the genome as a whole. This allows scientists to study the interactions among many genes and how they all contribute to a phenotype.

Gene Therapy

Gene Therapy: A technique aimed at correcting the effects of a mutated gene that is associated with a genetic disorder by inserting the correct form of the gene into the genome of the patient.

o A copy of the normal gene is inserted into a vector, which acts as a carrier of the gene.

o The vector is usually the DNA of a virus, because viruses can easily infect human cells.

o Once the virus delivers the normal gene to the human cell, the correct protein that is made from the gene is produced.

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