Review 8 Important Vocabulary Gene piece of a chromosome that codes for a trait Trait a specific characteristic that varies from one individual to another You are your parents Dads chromosomes ID: 1034134
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1. Buckle Down – Genes and AllelesReview 8
2. Important VocabularyGene – piece of a chromosome that codes for a traitTrait – a specific characteristic that varies from one individual to another
3. You are your parents!Dad’s chromosomesMom’s chromosomes
4. Genes in PairsYou have 23 PAIRS of chromosomesAllele from each parentCan be dominant or recessive
5. Phenotype and GenotypePHenotype: What you see (PHysical appearance)ie.: blue eyes, blonde hairGENotype: The GENes you haveie.: Bb, BB, bb (Heterozygous, homozygous, etc)
6. Review Break!What do we know so far?Gene – piece of a chromosome that codes for a traitTrait – a characteristicYou get ½ your genes from mom, ½ from dadEach gene has 2 alleles (one from mom, one from dad)An allele is dominant or recessiveDominant (T) will always be seen, recessive (t) will be seen if there is no dominantPhenotype is physical (what you see)Genotype is the gene itself (Tt, tt, or TT)Turn to page 117…Is “detached ears” a phenotype or genotype?What genotype produces white flowers in a pea plant?
7. Ratio?Flipping a coin:50% chance of landing heads up, is a 1:1 ratioIf you flipped a coin, compared to your partner, compared to the room…Would there be an expected ratio? Is it guaranteed?
8. Genetics BasicsAlleles shown using variables (2 alleles per gene, one from each parent) such as T or t“Heterozygous” if it is hybrid (Tt) “Homozygous Dominant” (TT) if pure dominant“Homozygous Recessive” (tt) if pure recessive
9. When doing a PunnettAlleles are shown with variableCapital for dominant, lower case for recessiveMother goes on side, father goes on topParent alleles on outside, possible offspring genotypes insidePoint is to find all possible genetic variations and the probability for it to appear
10. TtTtTtTtProbability and PunnettTTTtTtttGenotypePhenotypeTTRed FlowerTtRed FlowerttWhite Flower
11. Punnett PossibilitiesIncomplete Dominance- Neither are completely dominant over the other (White x Red = Pink)Heterozygous means a new phenotype!
12. Incomplete Dominance TtTtTtTTTTttTtttGenotypePhenotypeTTRed FlowerTtPink FlowerttWhite Flower
13. Punnett PossibilitiesCodominance- Both alleles contribute to phenotype (Pink x White = Speckled pink and white)
14. Codominance TtTtTtTTTTttTtttGenotypePhenotypeTTRed FlowerTtRed and White FlowerttWhite Flower
15. Punnett PossibilitiesMultiple alleles- More than two allelesBlood types!IA = allele for A-typeIB = allele for B-typei = allele for O-type
16. Multiple AllelesBAIBiIAIAIBIAiiIBiiiGenotypePhenotypeIAIAA-TypeIAiA-TypeIBIBB-TypeIBiB-TypeIAIBAB-TypeiiO-Type
17. Punnett PossibilitiesSex-Linked Traits- genes found on the XY chromosomeColorblindness(XC vs. Xc vs. Y)Page 121
18. Multiple AllelesXCYXCXcXCYXCXCXCXCYXcXCXcXcYGenotypePhenotypeXCXCFemale NormalXCXcFemale ColorblindXCYMale NormalXcYMale Colorblind
19. Review Break!What do we know so far?You get ½ your genes from mom, ½ from dadAlleles are assorted randomlyPunnett Squares are used to determine chances of a trait occurring Incomplete Dominance- Neither are completely dominant over the other Codominance- Both alleles contribute to phenotype Multiple alleles- More than two allelesSex-Linked Traits- genes found on the XY chromosome
20. PedigreeTracks transmission of a trait through generationsCircles = females, squares = malesHorizontal lines = mating, vertical lines = offspringGenerations shown with Roman numeralsShaded = expressed trait
21. IIIIII 1 2 1 2 3 4 5 6 1 2 3 4 5 6 7 8 9Page 124