Science and Engineering Practices Disciplinary Core Ideas Crosscutting Concepts

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1 INVESIGAION Punne Squares Key Quesion: How are Punne squares used o make predicions abou inheriance? Sudens learn how o use Punne squares o predic he mos likely rais of he offspring of he creaures hey buil. wo groups work ogeher and mae he Crazy Creaures ha hey flipped for in he previous invesigaion. Sudens creae Punne squares o deermine he mos probable phenoype for each rai of he offspring. Sudens hen flip coins o see wha genoypes and phenoypes he offspring will acually have. his shows sudens ha even hough Punne squares can be used o predic he oucome, chance sill plays a huge role in geneics. Learning Goals Creae Punne squares o deermine he mos probable genoype and phenoype for a given cross. Make predicions wih Punne squares and es predicions. Calculae he probabiliy of inheriing a cerain genoype and phenoype. GEING SARED ime 50 minues Seup and Maerials 1. Make copies of invesigaion shees for sudens. 2. Wach he equipmen video. 3. Afer he invesigaion, have your sudens use he organizaion char (included in he Crazy rais se) o make sure hey have all of he pars. 4. Review all safey procedures wih sudens. Maerials for each group y Crazy rais se Online Resources Available a curiosiyplace.com y Equipmen Video: Crazy rais y Skill and Pracice Shees y Whieboard Resources y Animaion: Punne Square y Science Conen Video: Genoypes and Phenoypes y Suden Reading: Predicing Herediy Vocabulary Punne square a char ha shows all of he possible combinaions of alleles from wo parens NGSS Connecion his invesigaion builds concepual undersanding and skills for he following performance expecaion. HS-LS3-3. Apply conceps of saisics and probabiliy o explain he variaion and disribuion of expressed rais in a populaion. Science and Engineering Pracices Disciplinary Core Ideas Crosscuing Conceps Analyzing and Inerpreing Daa LS3.B: Variaion of rais Scale, Proporion, and Quaniy Crazy rais 77

2 Punne Squares BACKGROUND You can predic he genoypes and phenoypes of offspring if you know he genoypes of he parens. A Punne square shows all of he possible combinaions of alleles from wo parens. Each of he four boxes represens one possible genoype ha he offspring migh have. Alleles of he oher paren Alleles of one paren Possible genoypes of offspring You can use a Punne square o show Mendel s firs cross. He crossed a rue-breeding, purple-flowered plan wih a rue-breeding, whie-flowered plan. Since he purple-flowered plan is rue-breeding, i has wo dominan alleles. he genoype of he purple-flowered plan is PP. Since whie flowers are recessive, he only possible genoype for a whie-flowered plan is pp. As you can see, all of he offspring in Mendel s firs cross had a genoype of Pp. he purple allele was dominan; ha s why all of he plans in he firs generaion had purple flowers. As is shown below, a Punne square prediced hese resuls. he only possible genoype is Pp and he only possible phenoype is purple flowers. A rue-breeding whie flower (pp) A rue-breeding purple flower (PP) P P p P p P p p P p P p When you flip a coin, here is a 50 percen chance you ll ge heads and a 50 percen chance you ll ge ails. he way he coin lands is compleely random. Like flipping a coin, he chance of inheriing a cerain genoype and phenoype is random. Probabiliy is he mahemaical chance ha an even will occur. Probabiliy can be expressed as a fracion or a percenage. For example, suppose one ou of he four squares in a Punne square conains pp. he probabiliy of any offspring having pp is herefore 1/4. o conver his o a percenage, ake he numeraor of he fracion divided by he denominaor and muliply by = 25% herefore, here is a 25 percen chance of any offspring having he pp genoype. 78

3 5E LESSON PLAN Engage Ask sudens, Wha is he probabiliy ha a newborn baby will be a boy or girl? Sudens should guess ha he chance is 50:50. Here is a way ha you can model he deerminaion of sex. Obain wo clear conainers. Label one conainer MALE and he oher FEMALE. Use colored beans o represen he sex chromosomes. For insance, you may use black beans o represen male (Y) and whie beans for female (X). Place an even number of whie beans (a leas 10) in he female jar. Place he same number of beans in he jar labeled male, bu ensure ha half he beans are whie and he oher half are black. Blindfold or cover he eyes of a suden voluneer. Ask he suden o choose one bean from each jar. Make a daa able on he board o record he daa. Reurn each bean o he jar from which i was aken. Repea his process 20 imes. A he conclusion, discuss he number of male and female offspring. Was he raio of males o females 1:1? Also, have sudens explain he imporance of selecing one bean from each jar. Complee Invesigaion, Punne Squares. In his invesigaion, sudens learn how o use Punne squares o predic he mos likely rais of he offspring of he creaures. Explain Revisi he Key Quesion o give sudens an opporuniy o reflec on heir learning experience and verbalize undersandings abou he science conceps explored in he invesigaion. Curiosiyplace.com resources, including suden readings, videos, animaions, and whieboard resources, as well as readings from your curren science exbook, are oher ools o faciliae suden communicaion abou new ideas. Science Conen Video Genoypes and Phenoypes Elaborae Animaion Punne Square Afer he invesigaion, have sudens revisi he daa from he Engage aciviy. Ask hem o creae a Punne square ha predics he probabiliy of offspring being male or female. Remind hem ha he genoype for a female is XX and a male is XY. Evaluae y During he invesigaion, use he checkpoin quesions as opporuniies for ongoing assessmen. Afer y compleing he invesigaion, have sudens answer he assessmen quesions on he Evaluae suden shee o check undersanding of he conceps presened. Crazy rais 79

4 Punne Squares Punne Squares How are Punne squares used o make predicions abou inheriance? INVESIGAION NASA is seing up an educaional exhibi o each people abou Crazy Creaures and heir plane, Geneicus. NASA has asked you o help hem selec he iniial breeding pair o include in heir exhibi. hey wan o be sure ha he parens ha hey pick and heir offspring will represen a variey of all he rais ha Crazy Creaures can have. You know ha you can predic he genoypes and phenoypes of offspring if you know he genoypes of he parens. A Punne square shows all he possible combinaions of alleles from wo parens. In his invesigaion, you will creae Punne squares o help NASA selec he bes creaures for heir new display. Using a model o make predicions Look a his Punne square showing he parens from he B3 invesigaion for all he rais. he wo alleles for each of he parens are shown ouside he squares one paren across he op and one paren down he side. Since each paren gives a leas one allele o heir offspring, he squares represen he four possible combinaions of alleles ha he offspring could receive. a. Wha are he possible genoypes of he offspring? Possible genoypes:,, Name Dae Maerials: Crazy rais se = 1/4 = 25% = 2/4 = 50% = 1/4 = 25% INVESIGAION 1. You will predic he probable rais of he offspring of wo Crazy Creaures o see if hey are suiable candidaes for he NASA educaion exhibi. You will work wih anoher eam and use he creaures you creaed in he las invesigaion. Your eacher will pair you up wih anoher eam ha has a creaure of he opposie sex. 2. he gender row of able 1 has been parially filled in for you. Since here is a 50% chance of he offspring being male or female, you will guess wha sex you hink he offspring will be. Fill in your predicion in he prediced phenoype column. 3. Now, fill in he genoypes for he moher and faher for all he oher rais in columns 2 and 3 in able For each rai, make a Punne square o show he possible combinaions of alleles for he offspring. 5. Deermine he mos probable phenoype by figuring ou which percenage of offspring would have each genoype. hen, use able 2 o deermine which phenoype is associaed wih ha genoype. Fill in he mos likely phenoype in column 4 of able 1. In he case of gender, you will find ha here is an equal chance of having eiher phenoype wo would have one rai, while he oher wo would have he oher rai. If his is rue, you can guess wha gender you hink ha he offspring will mos likely have. 6. Nex, wrie he fracion o show wha subse of he offspring would mos likely have he prediced phenoype. You can creae a fracion by using he number of boxes showing offspring wih each genoype divided by four (he oal number of squares). Use his fracion o find he percen in sep Finally, find he percen of he offspring ha would mos likely have he prediced phenoype. o calculae a percen, divide he numeraor by he denominaor and muliply by 100. Record he percen in column 5 of able Repea hese seps for rais 3 hrough 14. Probabiliy plays an imporan role in herediy. Alhough we can use Punne squares o show he possible oucomes, he acual chance of inheriing a cerain genoype or phenoype is sill random. Probabiliy is he mahemaical chance ha an even will occur. Probabiliy can be expressed as a fracion or a percenage. Since here are four possibiliies in Punne squares, i is easy o make fracions: 1/4, 2/4 or 1/2, 3/4, and 4/4 or 1. o conver hese fracions o percenages, ake he numeraor of he fracion divided by he denominaor and muliply by 100, as shown above. b. Wha is he probabiliy ha he offspring will show he dominan phenoype? he probabiliy is 3/4, or 75%. (25% + 50% ) Copyrigh CPO Science Can be duplicaed for classroom use 1 of 6 Punne Squares Crazy rais Copyrigh CPO Science Can be duplicaed for classroom use 2 of 6 Punne Squares Crazy rais SEM CONNECION How are Punne squares used in medicine? Cysic fibrosis (CF) is an inheried disease ha causes hick, sicky mucus o form in he lungs and oher organs. In he lungs, his mucus blocks he airways, causing lung damage and making i hard o breahe. People wih CF have a shorer-han-normal life expecancy. he good news is ha as reamens for CF improve, he life expecancy for people wih he disease is rising. oday many people wih he disease live ino heir 30s, 40s and beyond. Physicians and geneic counselors ofen use Punne squares as predicive ools for parens who are considering having children if a geneic disorder, like cysic fibrosis, is presen in heir family hisory. Imagine a couple who boh have a hisory of cysic fibrosis in heir families. Of course, hey are worried abou wheher heir children will be healhy or have he disorder. 80

5 able 1: Prediced phenoypes and probabiliy Genoype of Prediced % Probabiliy faher phenoype INVESIGAION 1 rai 2 Genoype of moher 6 Acual genoype 7 1. Sex XX XY male 50% XY male 2. Skin color purple 50% red Acual phenoype 3. Leg shor 100% shor 4. Foo webbed 100% webbed 5. Arms long 50% shor 6. Hands paws 100% paws 7. Eye color red 100% red 8. Eyebrows unibrow 75% unibrow 9. Beak crusher 50% rumpe 10. Ears mouse 50% mouse 11. Anenna lengh long 75% shor 12. Anenna shape knob 100% knob 13. ail shor 100% shor 14. Wings no wings 100% no wings Answers will vary. Sample answers above. able 2: Key o genoypes and phenoypes INVESIGAION rai Genoypes and phenoypes 1. Sex XX female XY male 2. Skin color red purple blue 3. Leg shor shor long 4. Foo webbed webbed alon 5. Arms long long shor 6. Hands paws paws claws 7. Eye color red one red and one green green 8. Eyebrows unibrow unibrow separae 9. Beak rumpe rumpe crusher 10. Ears elephan elephan mouse 11. Anenna lengh long long shor 12. Anenna shape knob knob sar 13. ail long shor none 14. Wings no wings no wings wings Sop and hink a. Wha is a Punne square? Wha informaion is needed o creae a Punne square? A Punne square shows all he possible combinaions of alleles from wo parens. You need o know he genoypes of he parens in order o creae a Punne square. b. Wha is probabiliy? Wha does probabiliy have o do wih inheriance? Probabiliy is he mahemaical chance ha an even will occur. I has o do wih inheriance because parens can only pass on one of heir wo alleles for each rai o heir offspring. I is random which allele each paren donaes. Copyrigh CPO Science Can be duplicaed for classroom use 3 of 6 Punne Squares Crazy rais Copyrigh CPO Science Can be duplicaed for classroom use 4 of 6 Punne Squares Crazy rais SEM CONNECION (coninued from previous page) Boh parens suspec ha hey carry he recessive allele for cysic fibrosis. For his example, we can use A as being he dominan, normal allele and a as he recessive allele ha is responsible for cysic fibrosis. Le s assume ha boh parens are carriers bu do no show sympoms of he disorder. So he parens are boh heerozygous (Aa). Cysic fibrosis only affecs hose who are homozygous recessive (aa). he Punne square below makes i clear ha a each birh, here will be a 25% chance of he parens having a normal homozygous (AA) child, a 50% chance of a healhy heerozygous (Aa) carrier child, and a 25% chance of a homozygous recessive (aa) child who will have cysic fibrosis. If boh parens are carriers of he recessive allele for a disorder (like cysic fibrosis), all of heir children will have he following odds of inheriing i: 25% chance of being heerozygous normal and no carrying he recessive allele (AA) 50% chance of being a healhy carrier (Aa) 25% chance of having he geneic disorder (aa) A a A AA Aa a Aa aa Crazy rais 81

6 Punne Squares Checking he predicions INVESIGAION 1. Now, o simulae he randomness of inheriance, you will flip coins o see if your predicions are righ. he firs rai you will flip for is sex. Choose he male sex chromosome coin (X on one side and Y on he oher) and he female sex chromosome coin (X on boh sides). Flip he coins ono he able and record your resuls in he acual genoype column of able 1. For he oher rais, you ll need o use he correc egg and sperm coins for each paren. Use he daa in able 1 o find he parens genoype for each rai. hen, selec he egg and sperm coins ha have he correc alleles for ha genoype. For example, if he faher s genoype for skin color is, choose he sperm coin ha has a capial on boh sides of he coin. If he moher s genoype for skin color is, find he egg coin ha has a lower case on boh sides of he coin. 2. Flip he coins ono he able. Record your resuls in column 6 of able Use able 2 o look up he corresponding phenoype. Record he phenoype of he offspring in he las column of able Repea his procedure for all he rais. 5. Build your creaure and compare wih oher creaures in he class. Developing and using models a. Why do you need o choose differen egg and sperm coins for each rai and for each paren? You need o choose he correc egg and sperm coin because each rai is deermined by is own se of alleles. b. How many of he acual phenoypes mached your prediced phenoypes? Explain your resuls. Answers will vary. Sample answer: en of my predicions mached my acual resuls. Seven of he rais had 100% probabiliy of being one of he rais so I was sure ha I had hose predicions correc. he rais ha were spli (50%) forced me o guess. I was righ wo imes in ha siuaion. c. Which paren does your offspring share he mos rais wih, he moher, faher, or boh equally? Answers will vary. Sample answer: My creaure shares nine rais in common wih is moher and seven rais in common wih is faher. INVESIGAION d. Are Punne squares unnecessary if boh parens have he same genoype? Explain. I depends on wha genoypes he parens have. If boh parens are or, hen he Punne squares are unnecessary. If boh parens are, hen you need o use he Punne square. e. Wha are he possible percenages for probabiliy when using Punne squares? Explain why hese are he only possibiliies. he possible percenages are 100%, 75%, 50%, 25%, or 0% when using Punne squares. hese are he only possibiliies because each paren has wo alleles, which can combine four possible ways in he offspring. f. From your invesigaion, wha genoypes will you recommend o NASA for he iniial breeding pair for heir new exhibi? Explain your choices. Answers will vary. Sample answer: I would recommend for all rais for he parens. When wo parens are crossed, here is he greaes chance for diversiy of rais in he offspring. Some offspring will show he dominan phenoype, while some will show he recessive phenoype. If he parens are or for any rai, ha will limi he amoun of variaion and cause he offspring o have a higher chance of resembling he parens. Exploring on your own Make an informaional sign o display a he NASA educaional exhibi explaining Punne squares and probabiliy o he public. Your sign should show he genoypes and phenoypes of he parens. I should also explain why his pair was seleced. Also, be sure o include he appropriae Punne squares o show he predicions for he possible offspring. Answers will vary. Sign should include he genoypes and phenoypes of he parens. I should explain why his pair was seleced. I should include he Punne squares o show he predicions for he possible offspring. Copyrigh CPO Science Can be duplicaed for classroom use 5 of 6 Punne Squares Crazy rais Copyrigh CPO Science Can be duplicaed for classroom use 6 of 6 Punne Squares Crazy rais Guiding he INVESIGAION Developing and using models he goal of his par of he invesigaion is o reinforce he idea ha Punne squares are useful in making predicions abou herediy, bu because herediy is random, hey are no a guaranee of genoypes and phenoypes of he offspring. WRAPPING UP Inerne search here are many websies ha will help sudens find ou how o make Punne squares. Insruc sudens o use a search engine and ype in he words Punne square uorial. Once hey have masered he process, have sudens wrie a lis of insrucions on how o make a Punne square. 82

7 Evaluae INVESIGAION Name Dae 1. Wha is he phenoype for a Crazy Creaure wih a genoype of for beak? rumpe beak 2. Wha is he genoype for a Crazy Creaure wih mouse ears? 3. If a homozygous dominan () paren maed wih a homozygous recessive () paren, wha is he probabiliy of he offspring having he dominan phenoype? Show he Punne square wih your answer. 100% dominan 4. If a heerozygous () paren maed wih a homozygous recessive () paren, wha is he probabiliy of he offspring having he homozygous recessive () genoype? Show he Punne square wih your answer. 50% recessive genoype 5. Why couldn wo Crazy Creaures wih separae eyebrows ever produce an offspring wih a unibrow? Explain your answer using a Punne square. wo parens for eyebrows could never produce an offspring wih a unibrow because hey don have a dominan allele o conribue. A leas one paren would need o have a dominan allele (and hus a unibrow) in order o have an offspring wih a unibrow. 6. Can a pure dominan () paren and a mixed-allele () paren ever produce a pure recessive () offspring? Explain your answer using a Punne square. No, because one paren () is always going o donae a dominan allele o he offspring. his means ha he offspring will display he dominan phenoype no maer wha he oher paren has for a genoype. Copyrigh CPO Science Can be duplicaed for classroom use Punne Squares Crazy rais Quesion 3: Quesion 5: Quesion 4: Quesion 6: Crazy rais 83

8 Punne Squares Noes and Reflecions 84