Name Class Date. Review Guide. Genetics. The fundamental principles of genetics were first discovered by. What type of plant did he breed?.

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1 Name Class Date Review Guide Genetics The fundamental principles of genetics were first discovered by. What type of plant did he breed?. True-breeding parental plants are called the generation. Their hybrid offspring are called the generation. What is the F2 generation? A monohybrid cross is the mating of two parents that differ in. Define the following terms: Gene: Allele: Homozygous: Heterozygous: Dominant Allele: Recessive Allele: Co-dominance: Incomplete Dominance: Polygenic: Sex-linked gene: Carrier:

2 What does the Law of Segregation state? Describe the difference between an individual s genotype and their phenotype: How can two plants with different genotypes for a particular gene be identical in phenotype? If an individual is heterozygous (Gg) for a gene, then according to the law of segregation, each gamete formed by this individual will have either the allele or the allele. What is the name of the process that cells go through to form gametes? Set up a Punnett square for this monohybrid cross: Pea plant that is homozygous recessive for flower color crossed with a pea plant that is heterozygous for flower color. What are the possible phenotypes that this mating could produce? In what ratio would these phenotypes occur? What is a dihybrid cross? What does the Law of Independent Assortment state?

3 Dihybrid cross problem: You are observing the inheritance of two different genes in Labrador retrievers the gene for coat color and the gene for vision. A black coat color is dominant over a brown coat color, and normal vision is dominant over blindness. You breed two dogs that are heterozygous for both genes. Assign alleles to: black coat: normal vision: brown coat: blindness: Assign genotypes to each parent in your cross: x What are the allele combinations in the gametes of each parent? Create a Punnett square that shows the possible genotypes of the offspring: What is the phenotypic ratio of the offspring? If a mother is a carrier of Tay-Sachs disease, an autosomal recessive disorder, and her husband is healthy and not a carrier What are the genotypes of the parents? What are the chances that their children will have the disease? Draw a pedigree of this family if they have two boys and two girls.

4 How can a child inherit a recessive disorder if both parents are not affected by the disease? An example of incomplete dominance is humans: Hypercholestemia A recessive allele can cause hypercholestemia dangerously high blood cholesterol levels. What kind of cholesterol levels would be found in an individual who o o Is homozygous dominant (HH)? Is heterozygous (Hh)? o Is homozygous recessive (hh)? The ABO blood group phenotype in humans involves three alleles of a single gene. How do we symbolize these three different alleles? Both the allele and the allele are dominant to the allele. The A and B alleles are, because both alleles are expressed in heterozygous individuals. How is codominance different from incomplete dominance? What are the names of the human sex chromosomes? Females have while males have. A human female s gametes all contain one chromosome, while a human male s gametes all contain either or chromosome. A gene located on either sex chromosome is called a, although the term refers specifically to a gene on the chromosome.

5 White eye color in fruit flies is an X-linked recessive trait. If a female fruit fly homozygous for red eyes is mated with a white-eyed male, will any of their offspring have white eyes? Explain. A female, red-eyed fruit fly that is a carrier of the recessive allele is mated with a red-eyed male. Draw a Punnett square to show the potential genotypes of their offspring. In what ratio do the phenotypes occur? Why is that only male offspring produced from this cross could possibly have white eyes? In order for a female with white eyes to be produced, it would have to inherit.

6 Why do sex-linked recessive disorders affect males more often than females? Why is it that only females can be considered carriers of a sex-linked disorder? Name two sex-linked recessive disorders in humans: Practice Problems 1. A couple are both phenotypically normal, but their son suffers from hemophilia (sexlinked recessive). What fraction of their potential children are likely to suffer from hemophilia? What fraction are likely to be carriers?