Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

Monthly Update sign up
Mailing List signup
Search
Follow The Annenberg Learner on LinkedIn Follow The Annenberg Learner on Facebook Follow Annenberg Learner on Twitter
Rediscovering Biology Logo
Home
Online TextbookCase StudiesExpertsArchiveGlossarySearch
Online Textbook
Back to Unit Page
Unit Chapters
Genomics
The Human Genome Project
Sequencing a Genome
Finding Genes
Is the Eukaryotic Genome a Vast Junkyard?
The Difference May Lie Not in the Sequence but in the Expression
Determining Gene Function from Sequence Information
The Virtues of Knockouts
Genetic Variation Within Species and SNPs
Identifying and Using SNPs
Practical Applications of Genomics
Examining Gene Expression
Ethics
Epilogue
Proteins & Proteomics
Evolution & Phylogenetics
Microbial Diversity
Emerging Infectious Diseases
HIV & AIDS
Genetics of Development
Cell Biology & Cancer
Human Evolution
Neurobiology
Biology of Sex & Gender
Biodiversity
Genetically Modified Organisms
The Virtues of Knockouts

Gene prediction programs have been valuable in the preliminary identification of genes; however, they have limitations. Unless the gene of interest is homologous to a gene of known function, the function is generally still not known. A biological approach to determining the function of a gene is to create a mutation and then observe the effect of the mutation on the organism. This is called a knockout study. While it is not ethical to create knockout mutants in humans, many such mutants are already known, especially those that cause disease. One advantage of having a genome sequence is that it greatly facilitates the identification of genes in which mutations lead to a particular disease.

The mouse, where one can make and characterize knockout mutants, is an excellent model system for studying genetic diseases of humans; its genome is remarkably similar to a human's. Nearly all human genes have homologs in mice, and large regions of the chromosomes are very well conserved between the two species. In fact, human chromosomes can be (figuratively) cut into about 150 pieces, mixed and matched, and then reassembled into the 21 chromosomes of a mouse. Thus, it is possible to create mutants in mice to determine the probable function of the same genes in humans. Genetic stocks of mutant mice have been developed and maintained since the 1940s.

One goal of the mouse genome project is to make and characterize mutations in order to determine the function of every mouse gene. After a particular gene mutation has been linked to a particular disorder, the normal function of the gene may be determined. An example of this approach is the mutated gene that resulted in cleft palates in mice. The researchers found that the gene's normal function is to close the embryo's palate. An understanding of the genetics behind cleft palate in mice may one day be used to help prevent this common birth defect in humans.

Back Next


© Annenberg Foundation 2014. All rights reserved. Legal Policy