Commack Schools



Genetics BasicsPeriod: ______ Date: ______________IntroductionHeredity is the characteristics that are transmitted from 2 parents to their offspring. Depending on the alleles that are passed on by the parents, the offspring’s genes will express certain traits. In this activity, you will work with your group to explore the basics of heredity.Model 1: GeneticsGronckles: Gronckles are gigantic dragons. Gronckles have a gene that controls the size of their wings. There are 2 variations of that gene: the B allele and the b allele. The B allele expresses the trait of big wing. The b allele expresses the trait of little wing. What is the gene in the paragraph above? ____________________________What are the alleles that control the size of the Gronckle’s wings? ________________ & __________________What are the two traits that can be expressed? _________________________ and _______________________Monstrous Nightmares: Monstrous Nightmares are dragons that are known for their fire breathing ability, but not all Nightmares can breathe fire. This dragon has a gene which controls whether it can or cannot breathe fire. There are 2 variations of that gene, the F allele and the f allele. The F allele expresses the trait of fire breathing ability. The f allele expresses the trait of not being able to breathe fire.What is the gene in the paragraph above? ___________________________What are the alleles that control fire breathing ability? _______________ & __________________What are the two traits that can be expressed? ________________________ & _______________________Based on the information above, come up with a definition for a gene. ____________________________________________________________________________________________________________________________Based on the information above, come up with a definition for an allele. ___________________________________________________________________________________________________________________________Based on the information above, come up with a definition for a trait. _____________________________________________________________________________________________________________________________Model 2: Dominant and RecessiveDragon Genetics KeyN = LONG NECKn = short neckE = RED EYEe = white eyeH = HORN PRESENTh = horn absentF = FIRE BREATHINGf = not fire breathingG = GREEN BODYg = grey bodyL = LONG TAILl = short tailS = SPIKES ON END OF TAILs = no spikes on end of tailB = BIG WINGSb = little wingsDominant alleles are represented by _______________________ letters. Recessive alleles are represented by _______________________ letters.Which letters are used to represent the gene for body color? _________________________________________Which letters are used to represent the gene for neck length? ________________________________________Which letters are used to represent the gene for fire breathing ability? _________________________________List 2 dominant dragon traits: ________________________________ & ________________________________List 2 recessive dragon traits: _________________________________ & ________________________________Based on the information above, what is a dominant trait? ______________________________________________________________________________________________________________________________________Based on the information above, what is a recessive trait? ______________________________________________________________________________________________________________________________________Model 3: Heterozygous and HomozygousOffspring get 1 copy of each chromosome from their parents. This also means that they get 1 copy of every gene from their parents. Sometimes, the alleles that the offspring get are the same and sometimes they are different. When the two alleles are the same, they are called homozygous or purebred. When the two alleles are different, they are called heterozygous or hybrid. Label the following pairs of alleles are either homozygous (homo) or heterozygous (hetero).SS ___________ff ___________Hh ___________EE ___________Gg ___________Ll ___________hh ___________NN ___________ee ___________RR ___________Which genotypes would be considered purebred? __________________________________________________Which genotypes would be considered hybrid? ____________________________________________________Model 4: Genotype and PhenotypeGene AGenotypePhenotype NNlong neckNnlong necknnshort neckGene BGenotypePhenotypeEEred eyeEered eyeeewhite eyeWhat do the two genes in the table above control? _______________________ & _______________________What are the 2 alleles that control neck length? _______________ & _______________What are the 2 alleles that control eye color? _______________ & _______________What is a genotype? (Use the terms: dominant, recessive, heterozygous, and homozygous) ______________________________________________________________________________________________________________________________________________________________________________________________________What is a phenotype? ____________________________________________________________________________________________________________________________________________________________________What determines phenotype? ____________________________________________________________________________________________________________________________________________________________Extension QuestionsFrom what you learned, and using the data obtained from the tongue curling exercise, do you think that the tongue curling trait is dominant or recessive? Why?What is the difference between genotype and phenotype? Provide examples of each.A pea plant may be characterized as tall (T) or short (t). Please show a combination of alleles for the following:A heterozygous tall individual:A homozygous recessive individual:List at least 5 other traits, not discussed during this activity, that are controlled by dominant or recessive alleles? ................
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