Presentation on theme: "Chapter 14: The Human Genome"— Presentation transcript:
1 Chapter 14: The Human Genome What makes you, you?
2 14-1: Human Heredity What is a karyotype? Picture of chromosomes arranged in homologous pairsHomo means what?A typical human being has 46 chromosomes2 are sex chromosomesMale: XYFemale: XX44 are autosomesSee Figure 14-1 page 341Analyze this karyotype and identify the person’s sex
3 50:50 chance of being male or female XXSee the Punnett square on page 342XXXYXY
4 Pedigree Charts Tool used to show the relationships within a family Can show how a trait or genetic diseases is passed through generationsSee Figure 14-3 on page 342Who does a circle represent? What about a square? What does shading represent?
5 Human GenesThe human genome is our complete set of genetic informationIncludes tens of thousands of genesSequence of DNA determines characteristics like eye color, blood type, structure of proteins (just to name a few)Sequence completed in 2000
6 Genetic Disorders Recessive alleles Dominant alleles Co-dominant allelesSee pg. 345 Table 14-6Can you list a few genetic disorders?
7 14-2 Human Chromosomes Sometimes, things go wrong with the chromosomes Sex linked genesChromosomal disordersX-chromosome inactivation
8 Sex-linked genesThere is a special pattern of inheritance for genes located on the X and Y chromosomesSex linked = genes located on the sex chromosomesX chromosome is larger than the Y chromosomeMore genes on the X chromosome
9 Sex-linked genes (cont.) Why is this important?Boys are at a disadvantage!!Sex linked disorders include:Color blindness, hemophilia, Duchenne muscular dystrophyMales have 1 X chromosome (meaning, they only have to inherit one bad gene to get the disease)Women have 2 X chromosomes (it’s like a back up)They will be a carrier, but not affected
10 Chromosomal Disorders Most of the time, the mechanisms that separate chromosomes in meiosis works very well.But, things can go wrongCommon error: non-disjunctionnot coming apartNon-disjunction = abnormal # of chromosomesSee Figure page 352
11 Common Chromosomal Disorders Down’s SyndromeAutosomalTrisomy 21Take a look at Figure (pg. 353) … what do you notice?Sex chromosome disordersExtra or too few sex chromosomeTurners (female: XO)Klinefelter (male: XXY, XXXY,)
12 Human Molecular Genetics Gene therapyAn absent or faulty gene is replaced by a normal, working geneSequencing the human genomeEthical issues?