Unit 4 – Lecture 6 Dihybrid Cross a 4x4 representation of crossing TWO traits monohybrid = 1 trait w/ 2 alleles = 1 allele gamete each for 2x2 box dihybrid = 2 traits w/ 2 alleles EACH = 4 alleles = 2 allele gametes each for 4x4 box [one allele for each trait in each gamete] Solving a Dihybrid Determine the genotypes of each parent Given to you, or you have to solve for them Given: Parent #1 AABB Given: Parent #2 aabb Solving a Dihybrid Create your dihybrid cross [4x4] Solving a Dihybrid Determine Gametes: pair first allele of first trait with first allele of second trait AABB first gamete = AB Solving a Dihybrid Determine Gametes: pair first allele of first trait with second allele of second trait AABB second gamete = AB Solving a Dihybrid Determine Gametes: pair second allele of first trait with first allele of second trait AABB third gamete = AB Solving a Dihybrid Determine Gametes: pair second allele of first trait with second allele of second trait AABB fourth gamete = AB Solving a Dihybrid Determine Gametes: pair first allele of first trait with first allele of second trait aabb first gamete = ab Solving a Dihybrid Determine Gametes: pair first allele of first trait with second allele of second trait aabb second gamete = ab Solving a Dihybrid Determine Gametes: pair second allele of first trait with first allele of second trait aabb third gamete = ab Solving a Dihybrid Determine Gametes: pair second allele of first trait with second allele of second trait aabb fourth gamete = ab Solving a Dihybrid Label cross w/ parent gametes above / to left AB ab ab ab ab AB AB AB Solving a Dihybrid Fill in boxes: fill DOWN each column w/ whatever’s there AB AB AB AB ab A B A B A B A B ab A B A B A B A B ab A B A B A B A B ab A B A B A B A B Solving a Dihybrid Fill in boxes: fill ACROSS each column with whatever’s there AB AB AB AB ab AaBb A B AaBb A B AaBb A B AaBb A B ab AaBb A B AaBb A B AaBb A B AaBb A B ab AaBb A B AaBb A B AaBb A B AaBb A B ab AaBb A B AaBb A B AaBb A B AaBb A B Solving a Dihybrid Determine Genotype Ratios record all genotypes you have count and record number of each genotype AB AB AB AB ab AaBb AaBb AaBb AaBb AaBb: 16/16 [or 100%] ab AaBb AaBb AaBb AaBb ab AaBb AaBb AaBb AaBb ab AaBb AaBb AaBb AaBb Solving a Dihybrid Determine Phenotype Ratios count how many of each phenotype you have record # of phenotypes represented AB AB AB AB ab AaBb AaBb AaBb AaBb purple, round: 16/16 [or 100%] ab AaBb AaBb AaBb AaBb ab AaBb AaBb AaBb AaBb ab AaBb AaBb AaBb AaBb Solving a Dihybrid #2 Determine the genotypes of each parent Given to you, or you have to solve for them Given – both parents are heterozygous for both traits. Given: Parent #1 QqRr Given: Parent #2 QqRr Solving a Dihybrid Create your dihybrid cross [4x4] Solving a Dihybrid Determine Gametes: pair first allele of first trait with first allele of second trait QqRr first gamete = QR Solving a Dihybrid Determine Gametes: pair first allele of first trait with second allele of second trait QqRr second gamete = Qr Solving a Dihybrid Determine Gametes: pair second allele of first trait with first allele of second trait QqRr third gamete = qR Solving a Dihybrid Determine Gametes: pair second allele of first trait with second allele of second trait QqRr fourth gamete = qr Solving a Dihybrid Label cross w/ parent gametes above / to left QR QR Qr qR qr Qr qR qr Solving a Dihybrid Fill in boxes: fill DOWN each column w/ whatever’s there QR Qr qR qr QR Q R Q r qR q r Qr Q R Q r qR q r qR Q R Q r qR q r qr Q R Q r qR q r Solving a Dihybrid Fill in boxes: fill ACROSS each column with whatever’s there QR Qr qR qr QR QQRR Q R QQRr Q r QqRR qR QqRr q r Qr QQRr Q R Q QQrrr QqRr qR Qqrr q r qR QqRR Q R Q QqRrr qqRR qR qqRr q r qr QqRr Q R Q Qqrrr qqRr qR qqrr q r Solving a Dihybrid Determine Genotype Ratios record all genotypes you have count and record number of each genotype QR [not going to make QR Qr qR qr QQRR QQRr QqRR QqRr you do it for this one.. Qr just know how to] QQRr QQrr QqRr Qqrr qR QqRR QqRr qqRR qqRr qr QqRr Qqrr qqRr qqrr Solving a Dihybrid Determine Phenotype Ratios count how many of each phenotype you have record # of phenotypes represented QR 9/16 - purple, round 3/16 - purple, wrinkled 3/16 - white, round 1/16 - white, wrinkled Qr qR qr QR QQRR QQRr QqRR QqRr Qr QQRr QQrr QqRr Qqrr qR QqRR QqRr qqRR qqRr qr QqRr Qqrr qqRr qqrr