This unit will review the findings of Gregor Mendel and his pea plants and how Punnett squares and pedigrees can help us study genetics. On the following slides, the red sections highlight the key points . Underlined words = Vocabulary!. Unit 10 - Genetics. Find Someone Who.
This unit will review the findings of Gregor Mendel and his pea plants and how Punnett squares and pedigrees can help us study genetics.
On the following slides, the red sections highlight the key points.
Underlined words = Vocabulary!
"Punnett squares in genetic crossings." Biology. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010. Science in Context. Web. 14 Jan. 2014.
Heredity is the passing of traits from parents to offspring through their gametes.
Here is the family of Queen Victoria, the British monarch known for carrying the mutation for hemophilia.
The Smith family pedigree shows four generations of the trait inheritance for neurofibromatosis.
What can we learn about William & Liz’s family?
Extra credit! Choose one genetically linked trait or disease from your family to study.
EX Eye color, Hair type, Freckles, Dimples, Breast Cancer, Etc.
Draw your parents and your parents and your siblings (brothers & sisters); color code the specific trait.
Create a key for the symbols and trait.
How many generations does this pedigree show?
How many individuals in this pedigree are affected by a genetic disorder?
Is this disorder a dominant disorder? Explain. Turn and talk to your neighbor.
"pedigree." Experiment Central. U*X*L, 2010. Science in Context. Web. 14 Jan. 2014.
Slides 10 through 22 are review slides from middle school genetics. Our genetics pre-test will give you feedback on your knowledge of these slides; if you pass with 85% accuracy, you would NOT need to copy these slides, only review them.
"Widow's Peak." Experiment Central. U*X*L, 2010. Science in Context. Web. 8 Jan. 2014.
Detached earlobes are a dominant allele; attached earlobes are recessive. Illustration by Temah Nelson.
"earlobes." Experiment Central. U*X*L, 2010. Science in Context. Web. 8 Jan. 2014.
Sketch the following!
Reginald Punnett is one of the most “unknown” well-known scientists because he developed the Punnett square to model genetic probability.
He published Mendelism in 1905 to explain the concepts of Mendelian genetics.
A Punnett square is a chart used to predict and compare the genetic combinations that will result from sexual reproduction.
"Punnett Squares." Genetics. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010. Science in Context. Web. 8 Jan. 2014.
"Punnett squares in genetic crossings." Biology. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010. Science in Context. Web. 8 Jan. 2014.
Why is the Punnett Square to the left called a “monohybrid cross”? How many offspring will display the dominant trait versus the recessive trait? What genotypic ratio will be seen in the offspring? Turn and talk to your neighbor.
"Punnett Square with Monohybrid Cross." Science Online. Facts On File, Inc. Web. 14 Jan. 2014.
In 1911, the first chromosomal gene mapwas produced and showed the gene locations on the chromosomes of a fruit fly. The banding areas represent a named gene [EX NF1] that controls a specific trait(s).
Gene maps are now widely used in understanding genetic mutations and sickness since the human genome project.
You can actually download the “GATTACA” sequence for humans at the National Center for Biotechnology Information.
The map is based on the idea of linkage, which means that the closer two genes are to each other on the chromosome, the greater the probability that they will be inherited together. By following inheritance patterns, the relative locations of genes along the chromosome are established.
EX – in the first box, place a GGEe.
Ge Ge Ge Ge
Genes that are located on the X or Y chromosomes are called sex-linked genes.
Many sex-linked genes are found on the X chromosome (which contains more than 100 genetic disorders).
Colorblindness and hemophilia are just two examples of genes relating to the X chromosome.
The human Y chromosome is much smaller than the X and only contains a few genes.
Duchenne muscular dystrophy is a genetic disease due to the loss-of-function mutation. The bottom diagram shows a typical pedigree for inheritance of an x-linked trait such as Duchenne muscular dystrophy.
Which sex is most affected by this disorder? Why? How does the Punnett square relate to the information displayed in the pedigree? Turn and talk to your neighbor.
"Genetic trait of Duchenne muscular dystrophy." Biology. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010. Science in Context. Web. 14 Jan. 2014.