BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment L12 GRQs Patterns of Inheritance II Reading Objectives Explain and apply the terms complete dominance co dominance incomplete dominance and multiple alleles pleiotrophy polygenic variation autosomes and sex chromosomes Determine the types of gametes that form through independent assortment in a dihybrid and link this to metaphase I of meiosis Module 9 11 Incomplete dominance results in intermediate phenotypes 1 Compare contrast the terms complete dominance incomplete dominance and co dominance and give example of each Complete dominance One allele completely masks the effect of the other Example Purple flowers in pea plants P is dominant over p Incomplete dominance Neither allele is fully dominant and the heterozygote shows an intermediate phenotype Example In snapdragons red RR crossed with white rr results in pink Rr Co dominance Both alleles are fully expressed in the heterozygote Example Blood type AB where both A and B alleles are expressed equally Module 9 12 Many genes have more than two alleles that may be codominant 1 Mendel focused on traits that had two alleles A or a in which one was dominant and the other was recessive Yet many genes may have multiple alleles What is an example in your book of a gene that has multiple alleles ABO blood group system 2 How many alleles are there in this system three alleles A B and O 3 How many different genotypes are possible with these alleles What are they six genotypes AA AO BB BO AB OO Module 9 13 A single gene may affect many phenotypic characters 1 When one gene influences two or more characters we call this pleiotropy Many of the genetic disorders we will learn about have multiple symptoms or traits This is because whatever protein is defective usually does not function in only a single cell type or tissue All the parts of the body affected by a disorder indicate the cells that require this protein normally 2 As an example of pleiotrophy sickle cell disease has many symptoms and does what to Red blood cell shape Red blood cell count Blood flow Kidneys BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment sickle cell Red blood cell shape Becomes sickle shaped Red blood cell count Decreases causing anemia Blood flow Impaired leading to blockages in blood vessels Kidneys Can cause kidney damage due to impaired blood flow Module 9 14 A single character may be influenced by many genes 1 Whereas pleiotophy describes the multiple traits resulting from a single gene a polygenic many gene trait describes how multiple genes result in a single trait What is an example of a polygeneic trait skin color 2 Polygenic inheritance can be recognized how skin shades and heights bc uses continuous range of phenotypes 3 Height is another polygenic trait yet one s height can also be influenced from the environment how Nutrition and overall health during childhood can affect the growth and final height of an individual Module 9 15 The environment affects many characters 1 Are human traits more heavily influenced by genes or the environment genes and the environment with the extent varying depending on the traits Module 9 16 Chromosome behavior accounts for Mendel s laws 1 Figure 9 16 is important for showing how meiosis is linked to inheritance Pretend you have to give a short presentation to a group of students explaining this figure What would you say This figure demonstrates how meiosis explains Mendel s laws During meiosis homologous chromosomes separate ensuring that each gamete receives only one allele of each gene which is Mendel s Law of Segregation Additionally the independent assortment of chromosomes during meiosis explains how different traits are inherited independently following Mendel s Law of Independent Assortment BIOL 101 Guided Reading Questions GRQs Complete and submit this GRQ as a PDF before lecture and before your online Mastering Assignment STUDY REMINDER Have been using the questions at the end of each chapter to test your knowledge You might want to do this now or when you come back to review this chapter later
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