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Learn about human genetics, karyotyping, pedigree analysis, and gene therapy. Discover how DNA studies, mouse models, and genetic testing play crucial roles in understanding and treating genetic diseases. Explore ethical dilemmas and future challenges in genetic research.
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Studying Human Genetics • Karyotyping • Studies the number and kind of chromosomes in the nucleus • Enables researchers to identify chromosome abnormalities • Pedigree • Family tree • Transmission of genetic traits over generations
Human genetics • Human genome and Human Genome Project • Bioinformatics • Storage, retrieval, and comparison of DNA • Pharmacogenetics • Drugs customized to individual • Proteomics • Study of proteins encoded by human genome
Mouse models to study disease • Ethical issues in using humans as test subjects • Animal model is used instead • Example is cystic fibrosis, a genetic disease • Gene targeting used to produce mice homozygous or heterozygous for cystic fibrosis
Abnormalities in chromosome number and structure • Aneuploidy: missing or extra copies of certain chromosomes • Trisomy: trisomy 21 common form of Down syndrome • Monosomy: Turner syndrome
Meiotic nondisjunction • Sister chromatids or homologous chromosomes fail to move apart in meiosis • Cause of • Trisomy • Monosomy
Structural abnormalities in chromosomes • Translocations • Deletions • Fragile sites
Genetic diseases caused by single-gene mutations • Autosomal recessive disorder • PKU • Sickle cell anemia • Autosomal dominant disorder • Huntington’s disease • X-linked recessive • Hemophilia
Gene therapy • Normal allele is cloned • DNA introduced into certain body cells • One technical challenge is finding appropriate vector
Prenatal gene testing and counseling • Amniocentesis • Chorionic villus sampling (CVS) • Preimplantation genetic diagnosis (PGD)
Genetic screening • Identifies individuals who might carry a serious genetic disease • Newborn screening important in preventive medicine • Genetic counseling • Medical and genetic information given when there is a risk of abnormality
Genetic discrimination • Discrimination because of differences from the “normal” genome • Controversy regarding whether information should be given to insurance companies and employers • Issues of genetic privacy will become increasingly important