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Name: ____________________Date: _______________Period: ______Baby LabPre-Lab DiscussionHeredity is the passing on of traits, or characteristics, from parent to offspring. The units of heredity are called genes. Genes are found on the chromosomes in a cell. The combinations of genes for each trait occur by chance.When one gene in a pair is stronger than the other gene, the trait of the weaker gene is masked, or hidden. The “stronger” gene is the dominant gene, and the gene that is masked is the recessive gene. Dominant genes are written as capital letters and recessive genes are written as lowercase letters. If both genes in a gene pair are the same, the trait is said to be homozygous, or pure-breeding. Sometimes genes are neither dominant nor recessive. The genetic makeup of an individual is known as its genotype. The observable physical characteristics of an individual that are the result of its genotype are known as its phenotype. In humans, the sex of an individual is determined by the particular combination of the two sex chromosomes. Individuals that have two X chromosomes (XX) are females, whereas those with an X and a Y chromosome (XY) are males. In this investigation, you will observe how the results of different gene combinations produce certain traits.ProblemHow are traits inherited?ProcedureEach partner must pick up one coin. You will flip the coin and write down the genotype. Using the parents’ genotypes, complete a Punnett square when asked, and also record the genotype and phenotype ratios for each Punnett Square.You now must now form your egg and sperm. For each chromosome, each parent will flip their coin and if they get head it will be the dominant allele if they flip tails it will be recessive.The alleles from each pair of chromosomes will be recorded in the data chart, recorded as the baby’s genotype.The decoding chart on page 2 indicates the phenotype of each gene. Use the chart to find the phenotype produced by your pair of alleles and record it in the data chart as the baby’s phenotype. Remember that a CAPITAL letter is dominant over a small letter [recessive] unless the decoding chart indicates those traits are incomplete dominance.Continue to flip the coin for each chromosome. After each flip, record your offspring’s new genotypes and phenotypes in the table.Human Baby GenomeDecoding of the GenesChromosomeDominant GenesRecessive GenesAutosome #1R. Round Facer. Square FaceH. [See Below]553339016510000313309016510000Autosome #2G. Widow’s Peak g. No Widow’s Peak E. [See Below]Autosome #3A. Almond Eyesa. Round EyesL. Long Eyelashesl. Short EyelashesAutosome #4N. [See Below]Autosome #5T. [See Below]Austosome #6F. Frecklesf. No FrecklesAutosome #7B. [See Below]D. Dimplesd. No dimplesIncomplete Dominance TraitsHH. Curly HairHh. Wavy Hairhh. Straight HairEE. Eye close togetherEe. Eyes medium distanceee. Eyes far apartNN. Large NoseNn. Medium Nosenn. Small noseTT. Thick LipsTt. Medium-sized Lipstt. Thin lipsBB. Large EarsBb. Medium Earsbb. Small earsData Tables:Autosome #1Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyDraw a Punnett Square for Shape of Face, and record the genotype and phenotype ratios possible for the offspring:EXAMPLE!!!RR RRRRRrRrRrGenotype Ratio:2RR : 2RrPhenotype Ratio:4 round : 0 SquareDraw a Punnett Square for Texture of Hair (curly vs. wavy vs. curly), and record the genotype and phenotype ratios possible for the offspring:Autosome #2Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyDraw a Punnett Square for Widow’s Peaks, and record the genotype and phenotype ratios possible for the offspring:Autosome #3Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyDraw a Punnett Square for Shape of Eyes, and record the genotype and phenotype ratios possible for the offspring:Autosome #4Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyAutosome #5Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyDraw a Punnett Square for Shape of Lips, and record the genotype and phenotype ratios possible for the offspring:Autosome #6Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyAutosome #7Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabySex Chromosomes Genotype of MomPhenotype of MomGenotype of DadPhenotype of DadGenotype of BabyPhenotype of BabyDraw a Punnett Square for the sex of a possible baby, and record the genotype and phenotype ratios possible for the offspring:ObservationsSex of offspring: ___________________Drawing of offspring (draw head only):TraitPhenotype of BabyShape of FaceTexture of hairWidow’s PeakSpacing of eyesShape of eyesLength of EyelashesSize of noseSize of LipsFrecklesSize of EarsDimplesName: ____________________________Baby Lab QuestionsData Analysis and ConclusionsWhat is the probability (in percent) of “producing” a male offspring? A female offspring? Every pair in your class had the same female and male chromosomes for your “parents.” Would you expect the other pairs of students in your class to have an offspring similar to yours? Explain your answer?If a woman who is homozygous for almond-shaped eyes (AA) marries a man who is heterozygous for almond-shaped eyes (Aa), what are the possible genotypes and phenotypes of their children?You worked with traits that are called “incomplete dominance.” By looking at what occurs with the trait, what do you think that means? Provide evidence from the lab to support your claim.Critical Thinking and ApplicationDo you think that anyone in your class has all the same genetic traits that you have? Explain your answer. (YOU, and not your baby!)Do you think you would have some genetic traits similar to your grandparents? Explain your answer. (YOU, and not your baby!)Extra CreditHow might it be possible for you to show a trait when neither of your parents shows it? ................
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