THE HUMAN GENOME Molecular Genetics Human Heredity THROWBACKS

THE HUMAN GENOME Molecular Genetics

Human Heredity • THROWBACKS: • • In both cystic fibrosis and sickle cell disease, a small change in the DNA of a single gene affects the structure of proteins, causing serious symptoms. Karyotypes Sex chromosomes – male & female chromosomes 45 & 46 either XX or XY (hopefully) Autosomes – chromosomes 1 – 44 – undergo mitosis ABO blood groups – IA i or IA IA is genotype for phenotype A blood type PKU – phenylketonuria – recessive allele - autosomal Galactosemia – recessive allele - autosomal Tay-Sachs disease – recessive allele – autosomal Cystic fibrosis – recessive allele – autosomal

Human Heredity • PEDIGREE CHARTS • …show relationships within a family and follows certain traits throughout generations; autosomal vs X-linked & dominant vs recessive can be determined.

Human Heredity • PEDIGREE CHARTS

Human Heredity • Pedigree Chart Analysis Video

Human Heredity • Nondisjunction: common error in meiosis when homologous chromosomes fail to separate. “not coming apart” When this happens, abnormal numbers of chromosomes can find their way into gametes and chromosomal disorders occur.

Human Molecular Genetics • DNA fingerprinting: the process of determining an individual's DNA characteristics, called a DNA profile, that is very likely to be different in unrelated individuals, thereby being as unique to individuals as are fingerprints (hence the alternative name for the technique). • DNA profiling uses repetitive ("repeat") sequences that are highly variable, called short tandem repeats (STRs). • Most normal people’s genes are about the same sequences if they actually code for a protein – however – sequences that do not code for proteins (introns) are very specific to individuals and so these introns are used to identify people based on their DNA profile. • 1. DNA is cut with specific restriction enzymes • 2. Fragments are separated by size using gel electrophoresis • 3. Radioactive probes label the separate “bands” of DNA sample • 4. If enough combinations of restriction enzymes and probes are used, a pattern of bands is produced that can be distinguished statistically from the pattern of any other individual in the world. • 5. Can be obtained from blood, other bodily fluids and hair strands.