Transcript Genetics
Heredity The transmission of characteristics from one generation to the next. Genetics is the study of how heredity works. Gregor Mendel discovered particulate inheritance Who was Mendel (18221884)? Gregor Mendel was an Augustinian monk, and avid gardener and bee keeper, an experimental physicist, a teacher, and the founder of modern genetics. The Homunculus Preformationism – a tiny human called a homunculus is present in each sperm. Mendel discovered particulate inheritance: think meiosis DNA The molecule (particle) of heredity Chromosomes Long strands of DNA wrapped around histones Karyotype – boy or girl? Genes Exist on chromosomes Turn one on and a protein is made Allele Alternate forms of same gene A a More vocab! Genotype – which set of alleles (Aa) Phenotype – which trait (purple flower) Dominant – shows trait if AA or Aa Recessive – shows trait only if aa Homozygous – alleles are identical (AA or aa) Heterozygous – alleles are different (Aa) Question Are dominant phenotypes more common than recessive phenotypes? Your hypothesis? Yes / No Eye Color Brown eyes are dominant to blue eyes. What is your Phenotype? Widow’s Peak A widow’s peak is dominant to a straight hairline Hitch Hicker’s Thumb A hitch hiker’s thumb is a recessive trait. Bent Little Finger A bent little finger is dominant to a straight one. Hold your hand out in front of you with your fingers together. Earlobes Unattached earlobes is dominant to attached earlobes. Tongue Curl If you can curl your tongue, you have the dominant allele. Freckles Having freckles is dominant. Hairy Knuckles Any hair on your knuckles means you are dominant. Interlocking Fingers Left thumb over right thumb is dominant to right thumb over left thumb. Mendelian Traits Trait Genotype Phenotype Eye Color B? or bb Brown or blue Widow’s Peak W? or ww Present or absent Hitch Hiker’s Thumb H? or hh Can’t or can bend Bent Little Finger L? or ll Bent or straight Earlobe E? or ee Unattached or attached Tongue Curl T? or tt Curl or not Freckles F? or ff Present or absent Hairy Knuckles K? or kk Present or absent Interlocking Fingers P? or pp L over R or R over L Homework Find phenotype for your parents Find phenotype for all siblings Add information to your table Due Thursday