- Slides: 23
Dominant & Recessive Traits Hidden Genes
Dominant & Recessive Traits A Dominant Gene - will, if present, hide a recessive gene by producing proteins. Dominant Genes are represented by upper case letters: TT or BB. Ex: Tall Pea Plants, Brown Eyes
Dominant & Recessive Traits A Recessive Gene - can be hidden by the presence of a dominant gene. An organism must have two copies of the recessive gene for it’s proteins to be visible. Recessive genes are represented by lower case letters: tt or bb. Ex: Short Pea Plants, Blue Eyes
Dominant & Recessive Traits Phenotype - What an organism looks like. The gene controls the production of a protein which creates the appearance. Phenotypes can be descriptive: Tall, Short, Brown, Blue. Or phenotypes can written as: Dominant or Recessive.
Dominant & Recessive Traits Genotypes A Genotype - which genes (alleles) an organism has for a trait. Genotypes are written with letters: TT, Tt, tt, BB, Bb, bb Genotypes can also be described with three terms: Homogenous Dominant Heterogeneous Homogenous Recessive
Dominant & Recessive Traits Genotypes Homogenous Dominant - “same genes” Any organism with two dominant genes for a trait. The dominant phenotype will show. Ex: TT - Tall Pea Plant. Ex: BB - Brown Eyes.
Dominant & Recessive Traits Genotypes Heterogeneous - “different genes” Any organism with one dominant and one recessive gene for a trait. The dominant phenotype will show. Ex: Tt - Tall Pea Plant. Ex: Bb - Brown Eyes.
Dominant & Recessive Traits Genotypes Homogenous Recessive - “same genes” Any organism with two recessive genes for a trait. The recessive phenotype will show. Ex: tt - Short Pea Plant. Ex: bb - Blue Eyes.
Question 1 A dominate gene hides a recessive gene by? a. b. c. d. Covering it up. Destroying the recessive gene. Making proteins that show. Making a trait that blends the proteins.
Question 2 In order for a recessive gene to show? a. b. c. d. The organism must choose it. The organism must have two copies. The organism can’t have any dominate traits. The organism must have one dominate gene.
Question 3 A a. b. c. d. phenotype is? A genetic condition with mistakes. An organism with recessive traits. An organism with only dominate traits. An organism’s looks.
Question 4 Which of the following is not an example of a Genotype? a. b. c. d. Homogenous Dominate, i. e. TT Heterogeneous i. e. Tt Homogenous Recessive i. e. tt Heterogeneous Recessive i. e. tt
Dominant & Recessive Traits Punnett Squares Look Like: a window, a four-square court, ? ? ? They can - predict the ratios of phenotypes & genotypes of future offspring without have to do the breeding.
Dominant & Recessive Traits Punnett Squares First, you place the Genotype of the parents on the outside of the square.
Dominant & Recessive Traits Punnett Squares Then fill in the squares of offspring using the Parent’s genes as a guide.
Dominant & Recessive Traits Punnett Squares Then you write the Phenotypes & Genotypes of the F 1 offspring.
Dominant & Recessive Traits Punnett Squares Who will do the next cross?
Dominant & Recessive Traits Mendel Dominant & Recessive Genes weren’t lost Genes are “particles” Found He could Predict the ratios of traits in offspring.
Question 5 When a. b. c. d. you fill in a Punnett square? You list the “Parent” genotypes on the top & side of the square. You copy one of each of the parent’s genes into each square. You list any dominate genes first. You do all of these.
Question 6 Punnett a. b. c. d. squares show you? The Genotype & Phenotype of the offspring. The Genotypes of the offspring. The Phenotypes of the offspring. Only the parent’s genes.
Question 7 If an offspring has two lower case genes - tt? a. b. c. d. It’s Genotype is Heterogeneous. It’s Phenotype is Dominate. It’s Genotype is Homogenous Recessive. It’s Phenotype is Homogenous Dominate.
Question 8 If you cross Pp x PP then the offspring will be? a. b. c. d. 25% HD, 50% H, 25%HR 75% Dominate, 25% Recessive 50% HD, 50% HR 50% HD, 50% H
Dominant & Recessive Traits Hidden Genes