Concept Teaching Workshop SBI11U Stephanie Romanello Mendelian Genetics Concept Teaching Workshop SBI11U Stephanie Romanello

Curriculum Expectations D2: Investigate genetic processes, including those that occur during meiosis, and analyse data to solve basic genetics problems involving monohybrid and dihybrid crosses D3: Demonstrate an understanding of concepts, processes, and technologies related to the transmission of hereditary characteristics These are the overall expectations. Should I be looking over which specific ones I covered and include those too? Also, the first overall expectation (D1) is missing because it is the STSE expectation which addresses students looking into ethical/social implication of modern genetic technologies. My presentation didn’t cover this so I didn’t include this. Is this okay, or should I be adding this STSE aspect into the presentation?

Gregor Mendel Mid 19th century Austrian monk Mathematician Gardner Failed at being a science teacher Lots of cool facts, and the delivery is very modern and casual Difference between modern science videos and old ones– Bill Nye http://www.youtube.com/watch?v=GTiOETaZg4w

Why Peas? Have seven traits that are determined by the expression of a single gene

Why Peas? Flower structure Snapdragon trait because it normally self fertilizes Go over how Mendel cross pollinated these plants Flower structure

Mendel’s Experiments Previously thought that breeding two different traits would result in a blend Noticed that only one of the two contrasting traits were expressed

Mendel’s Conclusions Each parent contributes one allele to offspring A dominant allele is always expressed, even if the recessive one is present Pairs of alleles segregate during sex cell formation Lead into the next slide with conclusion 1

Meiosis Meiosis described in 1876 by observing sea urchins Mendel’s pea experiments were done between 1856 and 1863, so he actually got this idea of having to go from diploid to haploid (2n to n) Video Very detailed but I like the beginning You can easily see what is going on by dragging the slider http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter28/animation__how_meiosis_works.html

Aa Genes Allele Dominant Allele Recessive Allele Two or more alternate forms of a gene Located at the same position on homologous chromosomes Dominant Allele An allele whose expression is overpowered by the presence of the recessive allele Recessive Allele An allele whose expression is overpowered by the presence of a dominant allele Determined the phenotype only is the dominant allele is absent Aa

AA aa Aa Important Terms AA Aa aa Genotype Phenotype Homozygous The alleles an organism contains. Phenotype Round, Wrinkled Yellow, Green Axial, Terminal The observable traits of an organism that arise because of the interaction between genes and the environment, Homozygous AA aa A genotype in which both alleles of a pair are the same. Heterozygous Aa A genotype in which the alleles of a pair are different.

Mendel’s Laws Law of Segregation Law of Independent Assortment Allele pairs segregate during the formation of gametes (sex cells) and randomly unite upon fertilization Law of Independent Assortment Going over #2 later in the presentation because it related to multiple alleles Law 1 deals with the fact that they separate during meiosis and come back together during fertilization

Mendel’s Laws Law of Segregation Law of Independent Assortment Allele pairs separate independently during the formation of gametes. Implies that traits are transmitted to offspring independently from one another http://bcs.whfreeman.com/thelifewire/content/chp10/1002001.html

Creating a Personal Profile

Genetics Survey http://ciese.org/curriculum/genproj/traits/

Genetics Problems Non interactive, but still a guided problem set that can be good extra work for students having difficulties/on an IEP… Interactive, online problem set that allows students to check their work as they go http://www.biology.arizona.edu/mendelian_genetics/problem_sets/monohybrid_cross/01t.html http://biology.clc.uc.edu/courses/bio105/geneprob.htm

Monohybrid Crosses 1) In pea plants, smooth peas (S) are dominant to wrinkled peas (s). What are the genotypic and phenotypic ratios in a cross of two plants that are both heterozygous for the seed shape trait?

Dihybrid Crosses 2) In pea plants, S is the allele for the dominant, smooth shape and s is the allele for the recessive, wrinkled shape. Also, Y is the allele for the dominant, yellow pea and y is the allele for the recessive, green pea. What is the resulting phenotypic ratio of a cross between two individuals that are heterozygous for both traits?

Test Crosses The cross of an organism with a dominant phenotype (genotype could be AA or Aa) with an organism that is homozygous recessive for that trait (aa).  3) In humans, brown eye colour (B) is dominant over blue eye colour (b). A man has brown eyes and his wife’s eyes are blue. They have a child with blue eyes. What is the father’s genotype?  4) When considering peas, tall plants (T) are dominant over short ones (t). Two tall pea plants are crossed, producing 105 tall plants & 32 short plants.  What are the genotypes of both parents.

Why Peas? Have large amounts of individuals in their progeny. Compare the amount of individuals a pea plant and a human family produce in one generation– the pea plants give us nice workable numbers that can help us infer ratios Have large amounts of individuals in their progeny.

Incomplete Dominance

Codominance– Blood Type Alleles 5) In humans the blood groups are produced by various combinations of three alleles IA, IB, and IO. Blood type A is caused by either IA IA or IA IO; type B by IB IB or IBIO; type AB by IA IB; and type O by IOIO. Suppose a child is of blood type A and the mother is of type 0. What type or types may the father belong to?