BIO 2 GO! Punnett Squares Punnett Squares are used to predict the genotype and phenotype of all possible offspring.

Transcription

1 BIO 2 GO! Punne Squares Punne Squares are used o predic he genoype and phenoype of all possible offspring. Upon successful compleion of his uni, you should be able o do he following: 1. Draw and compleer a Punne Square 2. Predic he genoype and phenoype of an offspring by using a Punne Square. 3. Undersand he following erms: Punne Square genoype phenoype gene allele offspring heerozygous homozygous dominan recessive

2 Punne Squares A Punne square is used o predic all of he genoypes of he possible offspring beween wo parens. Ouside he box are leers represening genes in he sperm and eggs cells of he parens. In each square is he genoype of he possible offspring made by he ferilizaion of he egg and sperm o he lef and o he op of ha box. Suppose a heerozygous all pea plan () pollinaed a homozygous shor pea plan (). Each sperm in he pollen could only have one allele for heigh because during meiosis, is wo ses of genes were divided ino one se of genes. In oher words, each sperm could only have a or a. Each egg in he shor plan could only have one gene for he same reason. In oher words, each egg could only have a. So, o use a Punne square o predic he possible genoypes of he offspring, firs, you mus draw a box wih four squares, like so.

3 hen you mus add he leers represening he genes in he possible sperm and egg cells on he op of he columns and o he lef of each row. hen you mus fill in each box, wih he leers represening he genes from he egg and sperm o he lef and op of each box. Examine his square. Arrows have been drawn o show you how o fill in he box for he genes on he lef side. Examine his square. Arrows have been drawn o show you how o fill in he box from he op.

4 he final produc conains wo genes, one from he lef side (moher) and one from he op (faher). Finally, afer being filled in, he possible genoypes of he offspring can be prediced. he phenoype, wha rai he offspring will carry, can be deermined from he genoype. Each block represens a 1 ou of 4 chance ha he offspring will have ha genoype. REMEMBER HIS!!! When filled in, he Punne square shows he genoypes of all of he possible offspring. here is only a chance ha any of hese offspring could be produced. In his paricular case, hese parens have a 2 ou of 4 chance or he raio 2:2 (or 1:1) chance of having an offspring wih he genoype. here is a 2 ou of 4 chance or he raio 2:2 (same as 1:1) chance of having an offspring wih a genoype. herefore, hey have a 2:2 (1:1) chance of having a all offspring and a 2:2 (1:1) chance of having a shor offspring. Once he genoype possibiliies for an offspring have been deermined, he phenoype can also be deermined. Remember, he phenoype is he appearance of he organism. he genoype is he geneic make-up of he organism. In he above problem, he genoype for he faher is, his phenoype is all. he genoype for he moher is, her phenoype is shor. In his same problem, he offspring may be eiher a or a genoype. he phenoype for a individual is all. he phenoype for a individual is shor.

5 Your urn. Creae a Punne Square in he space below or on he back of his page. Assume ha C is dominan for black eyes and c is recessive for red eyes in an organism. Wha are he chances ha he offspring of a homozygous dominan faher and a homozygous recessive moher will have a black eyed offspring? he faher s genoype is CC, he moher is cc.

6 es Yourself 1. Assume ha D is dominan for brown hair in rabbis and d is recessive for albino or whie hair. In he space below, use a Punne square o deermine he odds of a heerozygous faher and a homozygous recessive moher having an albino offspring. 2. Creae a Punne Square and predic he genoype and phenoype of all offspring for a cross beween a green skin color male and a green skin color female for a species of amphibian. Assume ha green is dominan G, and blue g is recessive. he faher and moher are boh heerozygous dominan, Gg.

7 Maching 1. Punne square 2. offspring genoypes 3. gamees 4. offspring phenoypes a. Leers wrien ouside he Punne square b. Leers wrien inside he Punne square c. diagram used o predic he genoypes of possible offspring beween wo parens d. inferred from he genoypes inside he Punne square. Pu in he Proper Sequence Afer being filled in, he possible genoypes and phenoypes of he offspring can be prediced. You mus add he leers represening he genes in he possible sperm and egg cells on he op of he columns and o he lef of each row. You mus fill in each box, wih wo leers represening he genes from he egg and sperm o he lef and op of each box. You mus draw a box wih four squares.

8 rue or False 1. A Punne square is used o predic all of he genoypes of he possible offspring beween wo parens. 2. All of he genoypes of he offspring are wrien ouside he box. 3. he leers ouside he box represen genes in he sperm and eggs of he parens. 4. he leers in each square represen he genes in he sperm and eggs of he parens. 5. he leers in each square represen he genoypes of he possible offspring. 6. If a male paren has he genoype, he can only make sperm wih one in hem. 7. If a male paren has he genoype, he can make sperm wih in hem. 8. If a male paren has he genoype, he can make some sperm wih in hem, and some sperm wih in hem. 9. If a female paren has he genoype, she can only make eggs wih one in hem. 10. If a female paren has he genoype, she can make eggs wih in hem. 11. If a female paren has he genoype, she can make some eggs wih in hem, and some eggs wih in hem. 12. An offspring from a paren ha is and anoher paren ha is could be. 13. An offspring from a paren ha is and anoher paren ha is could be. 14. An offspring from a paren ha is and anoher paren ha is could be

9 Fill in he Blanks Punne square gamees genoypes phenoypes 1. If a paren has he genoype, i can only make gamees wih one in hem. 2. If a paren has he genoype, i can make some gamees wih in hem and some gamees wih in hem. 3. A can be used o show he genoypes of he possible offspring of a paren wih a genoype and a paren wih a genoype. 4. he genes in he are wrien as leers ouside he Punne square. 5. he of he possible offspring are wrien inside each square. 6. he possible can be deermined by inerpreing he possible genoypes of he offspring. Creae a Punne Square for he following even: If Y = he gene for yellow pea seeds and y = he gene for green pea seeds, wha would be he possible genoypes of he offspring of wo Yy parens. Possible genoypes of offspring are. Possible phenoypes of offspring are.