 Calculate and predict the genotypic and phenotypic ratio of offspring of dihybrid crosses involving unlinked autosomal genes.

 Genotype-The genetic makeup of an organism that includes their biological characteristics.

 Phenotype-The physical makeup of an organism that includes their physical characteristics Possible phenotypes Yellow Corresponding genotypes YY or Yy YY = 2 dominant Yy = one dominant, one recessive yy = 2 recessive green yy Round wrinkled RR or Rr rr

 Dihybrid Crosses involve two genes which control two characteristics.  We can use dihybrid crosses to calculate and predict the genotypic and phenotypic ratio of offspring involving unlinked autosomal genes.

 Autosomal Genes- A gene that is not located on a sex chromosome. *When a gene is unlinked, they are found on different chromosomes and can be segregated by Random Assortment of meiosis, during Metaphase II.

 In order to calculate the genotypic and phenotypic ratio: › 1) Determine the parent’s genotypes › › 2) Make and solve dihybrid cross 3) Calculate and predict genotypic and phenotypic ratios. › › http://www.siskiyous.edu/class/bio1/genetics/di hybrid_v2.html

http://www.sumanasinc.com/webcontent/anim ations/content/mendel/mendel.html

 Distinguish between autosomes and sex chromosomes .

  Autosomes- General chromosomes that carry genetic instruction and any chromosome other than a sex chromosome; come in pairs. Sex chromosomes- Come in pairs also, but there are two types, X & Y. For humans, the Y chromosome is the “determining factor” as it determines whether or not the embryo is male or female.

 Explain how crossing over between non sister chromatids of a homologous pair in prophase I can result in an exchange of alleles.

 Crossing over, also known as recombination, is the exchange of chromosome segments between non sister chromatids in meiosis.

 Alleles - an alternative form of a gene (one member of a pair) that are located at a specific position on a specific chromosom e. The DNA codings on an allele determine traits that are passed on from parents to offspring.

  During crossing over, “slices” of homologous chromosomes’ DNA are exchanged with non-sister chromatids of a homologous pair. Because of this, alleles are exchanged as the alleles from one chromatid are being exchanged with the alleles on a non-sister chromatid. http://highered.mcgraw hill.com/sites/dl/free/0072835125/126997 /animation5.html

         "Dihybrid Cross." The Biology Project. Web. 09 Feb. 2012. .

http://library.thinkquest.org/20830/Textbook/Genetics.htm

http://www.sumanasinc.com/webcontent/animations/content/me ndel/mendel.html

http://newton.dep.anl.gov/askasci/mole00/mole00388.htm

http://www.bookrags.com/research/crossing-over-gen-01/ http://en.wikibooks.org/wiki/IB_Biology/Genetics,pt2 http://click4biology.info/c4b/10/gene10.2.htm#1 http://highered.mcgraw hill.com/sites/dl/free/0072835125/126997/animation5.html

http://www.ibguides.com/biology/notes/dihybrid-crosses hl?PHPSESSID=8a17514703a1a528f6e35ae35079158d