Mendelian Genetics

A diagram showing the steps in determining the possible haploid gametes during independent assortment.

• Parental genotype
  Place the parental genotype in the center of your drawing.
  Identify the genes carried by homologous chromosomes, (Rr and Tt).
• Place the gametes
  Divide the diagram into four quarters.
  Place a potential haploid gamete in each quarter.
• Choose one set of genes that are carried by a pair of homologous chromosomes.
  In this case take the Rr combination.
  • Place the R gene in both the gametes above the horizontal line.
  • Place the r gene in both the gametes below the horizontal line.
  • Check your work.
  • Cross out the Rr genes - we are finished with them.
• Take the second pair of genes (Tt). These will be on a second set of homologous chromosomes.
  • Place the T gene in both the gametes to the left of the vertical line.
  • Place the t gene in both the gametes to the right of the vertical line.
  • Check your work.
  • Cross out the Tt genes - we are finished with them.
• The four possible haploid gametes that could be produced by Independent Assortment from the original parental cell are now in the four corners of the diagram.

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Mendelian Genetics - Topic Outline

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Science at a Distance
© 1997, Professor John Blamire