Chapters 13 and 14Chapters 13 and 14

Genetic Engineering,Genetic Engineering,The Human GenomeThe Human Genome

13.1 Changing 13.1 Changing the the Living WorldLiving World

• Selective breeding: controlling the passing Selective breeding: controlling the passing of desired traits to the next generationof desired traits to the next generation– Hybridization – crossing of 2 dissimilar Hybridization – crossing of 2 dissimilar

organisms to result in the best traits in the organisms to result in the best traits in the offspringoffspring

– Inbreeding – continued breeding of individuals Inbreeding – continued breeding of individuals with similar characteristicswith similar characteristics

• Increasing variation: induction of mutationsIncreasing variation: induction of mutations– To produce new desired characteristicsTo produce new desired characteristics– Polyploidy in plantsPolyploidy in plants

13.2 Manipulating DNA13.2 Manipulating DNA• Why?Why?

– Study DNA sequences and compareStudy DNA sequences and compare– Change DNA through genetic engineeringChange DNA through genetic engineering

• How?How?– DNA extraction by fractionationDNA extraction by fractionation– Cutting DNA by using restriction enzymesCutting DNA by using restriction enzymes– Separating DNA by gel electrophoresisSeparating DNA by gel electrophoresis– PCR, polymerase chain reaction, to amplify PCR, polymerase chain reaction, to amplify

DNA fragmentsDNA fragments

13.4 Applying 13.4 Applying Genetic Genetic EngineeringEngineering• Cell transformation: a cell that takes DNA Cell transformation: a cell that takes DNA

from outside the cell and incorporates the from outside the cell and incorporates the segment as part of its own DNA. The segment as part of its own DNA. The resultant organism is now transgenic.resultant organism is now transgenic.– Ex: the production of human insulin from Ex: the production of human insulin from

bacteriabacteria

• Cloning: Cloning: – one cell producing an organism with identical one cell producing an organism with identical

cellscells– More difficult in multicellular animalsMore difficult in multicellular animals– In 1997, a sheep was cloned (Dolly).In 1997, a sheep was cloned (Dolly).

Human Human ChromosomesChromosomes

• Karyotype: picture of condensed Karyotype: picture of condensed chromosomes that have been grouped in chromosomes that have been grouped in pairspairs

• Human body cells have 46 and their gametes Human body cells have 46 and their gametes 2323– 44 are autosomes44 are autosomes– 2323rdrd pair are sex chromosomes: pair are sex chromosomes:

• Female=X XFemale=X X• Male=X YMale=X Y

Human Traits and GenesHuman Traits and Genes

• Pedigree charts show relationships within familiesPedigree charts show relationships within families• Multiple alleles: Blood type: IMultiple alleles: Blood type: IAA, I, IBB, i, iO O and ± Rh and ± Rh

factorfactor• Recessive alleles: Disorders of PKU and Tay-Recessive alleles: Disorders of PKU and Tay-

SachsSachs• Dominant alleles: Disorders such as Huntington’s Dominant alleles: Disorders such as Huntington’s

Disease Disease • Sex-linked genes: color-blindness and hemophiliaSex-linked genes: color-blindness and hemophilia• Polygenic traits: skin color, eye colorPolygenic traits: skin color, eye color• Genetic disorders: cystic fibrosis and sickle cell Genetic disorders: cystic fibrosis and sickle cell

anemiaanemia

Chromosomal disordersChromosomal disorders

• NondisjunctionNondisjunction– Down’s Syndrome (extra 21Down’s Syndrome (extra 21stst

chromosome)chromosome)– Nondisjunction of sex chromosomes:Nondisjunction of sex chromosomes:

• Turner’s (XO) and Klinefelter’s Syndromes Turner’s (XO) and Klinefelter’s Syndromes (XXY)(XXY)

Human Molecular Human Molecular GeneticsGenetics

• DNA Analysis for DNA Analysis for

DNA “fingerprinting”DNA “fingerprinting”• Human Genome ProjectHuman Genome Project• Gene TherapyGene Therapy• Genetic Engineering: Genetic Engineering:

– Selective breeding, hybridization, Selective breeding, hybridization, inbreeding, restriction enzymes, gel inbreeding, restriction enzymes, gel electrophoresis, recombinant DNA, PCR, electrophoresis, recombinant DNA, PCR, transformation, cloningtransformation, cloning