1 / 16

Dihybrid Punnett Squares

Dihybrid Punnett Squares. You are a product of your family and your environment. Review: Monohybrid Cros. Autosomal Dominant/Recessive inheritance Predicting one trait at a time Mono=one. Dihybrid Worksheet. Autosomal Dominant/Recessive Inheritance Dealing with two traits at a time

jena
Download Presentation

Dihybrid Punnett Squares

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dihybrid Punnett Squares You are a product of your family and your environment.

  2. Review: Monohybrid Cros • Autosomal Dominant/Recessive inheritance • Predicting one trait at a time • Mono=one

  3. Dihybrid Worksheet • Autosomal Dominant/Recessive Inheritance • Dealing with two traits at a time • Di-hybrid(“di”= two) • Diagram to right: • Round vs wrinkled • Green vs yellow

  4. Hair color H=dark hair h= light hair Eye Color B=Brown b=blue Two phenotypic traits

  5. Mendel’s Law of Independent Assortment • Traits are caused by genes on different chromosomes • Ex. Gg Yy • Can form sperm or eggs that are GY, Gy, gY, or gy • Sorting of DNA into gametes is random of other chromosomes

  6. What type of gametes? • Person homozygous for dark hair and dark eyes • Genotype: HHBB • Gametes: only HB HH BB HB HB HB HB

  7. Heterozygous for one trait • What about a person heterozygous for dark hair and homozygous dominant for eye color • Genotype: HhBB • Gametes: HB or hB Hh BB hB HB HB hB

  8. Heterozygous for both traits • What gametes will a person heterozygous for both traits produce? • Genotype: HhBb • Gametes: HB, Hb, hB, hb Hh Bb hB HB Hb hb

  9. Dihybrid Worksheet Step 1 • Step 1: Determine genotypes of both parents • One parent is homozygous dominant for both traits … • Genotype: HHBB • …other parent is heterozygous for both traits. • Genotype: HhBb

  10. Step 2: List all possible gametes • Parent 1 genotype: HHBB • HB • Parent 2 genotype: HhBb • HB • Hb • hB • Hb • Your punnett square will be one by four squares long

  11. Step 3: Draw punnett squares • Dimensions depend on parent’s gametes • No longer simply two by two • Parent’s gametes are 1 and 4 so punnett square will be 1 by 4

  12. Step 4: • Take one parent and list possible gametes on appropiate side • Parent one had 1 possible gamete production(HB) HB

  13. Step 5 • Take other parent and list possible gametes along punnett squares • Parent 2 has 4 possible gametes(HB, Hb, hB, hb) HB Hb hB hb HB

  14. Step 6 • Carry out punnett squares and fill them in • Dihybrid is two traits: four alleles HB Hb hB hb HHBB HHBb HhBB HhBb HB

  15. Step 7 • Write genotype ratios • Genotype:1 HHBB:1HHBb:1HhBB:1 HhBb HB Hb hB hb HHBB HHBb HhBB HhBb HB

  16. Step 7 • Write the phenotype ratios • F1 phenotype: All dark hair/brown eyes HB Hb hB hb HHBB HHBb HhBB HhBb HB

More Related