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I. Heredity & Genetics parent to offspring oThe passing of traits from parent to offspring genes oTraits are controlled by genes
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II. ALLELES FORM oONE FORM of a gene one oSex cells have one two oBody cells have two forms or ALLELES for a single gene dominant oOne may be dominant over another.
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III. DOMINANT AND RECESSIVE mask oDominant will always be expressed and will “mask” recessive dominant oA recessive trait can only be expressed if there are no dominant alleles present.
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oExample dominant oExample: Eyecolor—Brown color is dominant and blue is recessive.
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capital lower caseDominant alleles are represented with a capital letter, recessive with a lower case letter.
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7 Albinism Recessive Alleles
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8 Cystic Fibrosis Recessive Alleles
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9 Dwarfism Dominant Alleles
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10 Sickle Cell Disease Recessive Alleles
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IV. GREGOR MENDEL father oFirst known geneticist and “father of genetics” 1822 oWas an Austrian monk and was born in 1822 pea oDid most of his genetic studies on pea plants
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oHe performed cross- pollination shapepeascolor seeds height position oMendel worked with shape of peas, color and shape of seeds, plant height, flower position and flower color.
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V. PROBABILITY chance oHelps predict the chance that something will happen 50% oExample: the probability of throwing heads or tails on a coin is 50% (1/2 chances) accurate oYour predictions become more accurate with the more trials you run!
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Why is it that if a couple has 2 children, they don’t always have one boy and one girl? 2 is a really small trial #…so won’t always “see” the ratio!
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VI. Using a Punnett Square oUsed to predict probability of traits otrait is givenTWO letters, one for each allele.
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same o“Purebred” =two alleles the same, BB or bb. otwo different alleles = “heterozygous”(hybrid). Bb genotype oThe alleles present = genotype. Ex. BB, Bb, or bb.
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PHENOTYPE oThe PHYSICAL trait =PHENOTYPE. oFor instance, Blue or Brown Eyes.
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Steps for using the Punnett square: (genotype) 1)One parent’s alleles (genotype) go on the top 2)The other parent’s alleles go down the side. 3)You fill in the squares like a multiplication table.
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Incomplete dominance Heterozygous expresses a different phenotype from either homozygous. Usually intermediate between the two. C R C R = Red C W C W = White C R C W = Pink
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Multiple alleles - Blood type 3 alleles, codominance A,B,o
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4 blood types from 3 alleles AA or Ao= type A BB or Bo= type B AB = type AB oo = type O
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DIHYBRID crosses 2 traits Heterozygous parents
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Polygenic inheritance = many genes for one character.
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SEX-LINKED and SEX INFLUENCED TRAITS
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SEX CHROMOSOMES CAN CARRY OTHER GENES TOO = ___________________ SEX LINKED TRAITS
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SEX LINKED TRAITS show up in different % in males and females because they move with the sex chromosomes
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Sex chromosomes can carry other genes Y-LINKED GENES: Genes carried on Y chromosome EX: Hairy pinna _________genes only show up in _______ Y linkedmales.
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Sex chromosomes can carry other genes X-LINKED GENES: Genes carried on the X chromosome EX: _____________ _____________ _________________________ Hemophilia Colorblindness Duchenne Muscular Dystrophy
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31 missing protein for normal blood clotting Hemophilia
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32 1 in 10 males in the US. Color Blindness
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33 1-100 females
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36 Duschenne Muscular dystrophy progressive weakening and loss of skeletal muscles
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SEX INFLUENCED TRAITS Genes ___________ on sex chromosomes BUT affected by ____________ of individual with gene not carried sex hormones
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How are genes passed on over generations?
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PEDIGREE CHART Normal Male = Normal Female = Has trait = Carrier =
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CARRIER Individual with one copy of a recessive autosomal allele Carriers DON’T SHOW the trait themselves but can pass it on to their offspring NORMAL DEFECTIVE
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Prenatal Diagnosis Amniocentesis Chorionic villus sampling Fetoscopy
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Prenatal Diagnosis Amniocentesis
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