Lab of genetics.You will determine your phenotype and try to determine your genotype for the traits listed below.

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Human Inheritance

Objectives:

  • Determine your phenotype for several traits.
  • Determine (as far as possible) your genotype for the same traits.

Procedures and Observations:

You will determine your phenotype and try to determine your genotype for the traits listed below. Remember, if you have a dominant trait, you may be homozygous or heterozygous fro that trait. If you know that one of your parents has the recessive trait, you must be heterozygous. If neither of your parents have the recessive trait, put a blank (_) for the unknown gene. If you possess the recessive trait, record it as the genotype, with two recessive genes.  

  • Free earlobes are dominant, L. people whose earlobes are attached directly to the side of the head have the recessive genotype, ll. Have your partner check your earlobes.
  1. Record your phenotype and genotype in a table. (Remember that if you have the dominant trait, you may not be able to determine whether your genotype is homozygous or heterozygous, in that case, record L_ in the table. The blank means an unknown gene).
  • Inheritance of eye color is controlled by multiple genes, but people having the homozygous recessive genotype, bb, have blue eyes. People who have a dominant gene, B, may have different shades of brown, hazel, or green eyes. Check your eye color.
  1. Record your phenotype and genotype in the table. (Remember that you may not be able to determine your exact genotype; in that case, record B_ in the table).
  • A Widow’s peak is a hairline that forms a downward point in the middle of the forehead. This is caused by a dominant gene, W. A smooth hairline is caused by the recessive genotype ww. Have your partner check your hairline.
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  1. Record your phenotype and genotype in the table.
  • A dominant gene, r, gives some people the ability to roll their tongue into a “U” shape when it is extended. People with the recessive genes, rr, cannot roll their tongues. Check to see if you can roll your tongue.
  1. Record your phenotype and genotype in the table.
  • A dominant gene, T, gives some people the ability to fold their tongues over. People with the recessive genotype, tt, cannot. Check to see if you can fold your tongue.
  1. Record your phenotype and genotype in the table.
  • A dominant ...

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