Models in Genetics

1. Models in Genetics Of Mice and Men Patricia Sidelsky BS/MS Biology Cherokee High School Marlton, NJ

2. What is a Genetic Model ? • Genes on chromosomes have been mapped • Genome has been sequenced • Significant for genetic content - relevance to man and society • Homologous in function or expression to man( Mice)

3. Genetic Models • Bacteria - E. coli • Yeast - Saccharomyces cerevisiae • Plants - Corn - Zea mays and Arabdopsis thaliana • Worm - C. elegans • Fruit fly - Drosophila melanogaster

4. Vertebrate Genetic Models • Zebra fish - Brachydanio rerio • Frog - Xenopus laevis • Mouse - Mus musculus

5. Why Mice? • Vertebrate Model • Mammal • Used in Biochemical research - Cae and housing easily managed • Short Generation time/ Breeding • Size of litter • Manipulation of embryos • 96% homologous in genetic content to man • 40,000 genes - similar in number to man

6. Mouse Models and Diseases • Epilepsy • Cystic fibrosis • Glaucoma • Heart Disease • Obesity • Parkinsons • Diabetes - Type I • Cancer

7. Mice and the Brain • Recently a model of the mouse brain has been completed that may lead to possible cures for diseases such as Multiple sclerosis or even Mental Disorders such as autism or schizophrenia

8. Early to Bed Gene • Gene has been located in mouse brain that regulates wakefulness and sleep of the mouse • Early to be gene • Located in a portion of the brain called the SCN( superchiasmatic nucleus)

9. Expression of Gene inMouse - Research on Sleeping Disorders in Humans • Narcolepsy • Cataplexy • Circadian rhythms

10. Mice and Science • Mice have been bred by mouse fanciers since the 1800’s • Abbie Lathrop, a Massachusetts mouse enthusiast began to breed mice in the early 1900’s for their interesting fur colors. • Harvard University began to use them in research • This led indirectly to the development of Jackson Laboratories in Maine

12. Many varieties of coat colors determined by a variety of genes The distribution and color of pigments Fancy Mice

18. Mouse Chromosomal analysis

19. Comparing a human and mouse gene significant in kidney disease

20. Genetic manipulation of mouse DNA • DNA is injected into early embryo • Genes are implanted that enhance or silence gene expression • New genes are incorporated into model organism genome

21. Designer Genes • 1. Make your DNA Using recombinant DNA methods, build molecules of DNA containing･the structural gene you wish to study • Make sure that you include with the gene the correct promoter and expression controls that you need

22. Gene Transfer • Transform ES cells in culture • Expose the cultured cells to the DNA so that some will incorporate it. • Select for successfully transformed cells. Inject these cells into the inner cell mass (ICM) of mouse blastocysts.

23. Transgenic Mice • Pronucleus Method • Transform fertilized eggs･Harvest freshly fertilized eggs before the sperm head has become a pronucleus.･Inject the male pronucleus with your DNA. • When the pronuclei have fused to form the diploid zygote nucleus, allow the zygote to divide by mitosis to form a 2-cell embryo.

24. Transgenic Mice

25. Reporter genes • Included and expressed with the gene of interest • My be expressed at the same developmental stage as well

26. Fluorescent Green Protein Marker

27. Growth Hormone • Promoter inserted to increase the production of growth hormone • Littermates displaying normal and transgene

28. Models for Human DiseaseObesity • Growing concern in obesity • Studying genes that effect weight maintenance and metabolism

29. Knock Out Mice • Gene is inactivated or nullified it is unable to be expressed • Knockout mice are valuable tools for discovering the function(s) of genes for which mutant strains were not previously available. • Knockout mice are often surprisingly unaffected by their deficiency. Many genes turn out not to be indispensable.

30. Knock Out Mice

31. Chimeric Mice

32. Chimeric Breeding

33. Thank you