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Autosomal Inheritance Bio 40S - Kelvin A trait expressed by a gene - PowerPoint PPT Presentation

Autosomal Inheritance Bio 40S - Kelvin A trait expressed by a gene located on an autosomal chromosome. Autosomal Traits 22/ 23 Chromosomes are autosomal, the exception being the X/Y sex chromosomes (but more on that later) Remember:


  1. Autosomal Inheritance Bio 40S - Kelvin

  2. A trait expressed by a gene located on an autosomal chromosome. Autosomal Traits 22/ 23 Chromosomes are autosomal, the exception being the X/Y sex chromosomes (but more on that later)

  3. Remember: Segregation and Independent Assortment Mendel developed two extremely important genetic laws. Law of Segregation: The factors of inheritance (genes) are normally paired BUT are separated or segregated in the formation of gametes.  The gene from each parent splits up, 50/50 chance of either Law of Independent Assortment: Each factor’s distribution in the gametes is not related to the distribution of any other factor.  Genes for hair colour and eye colour arrange separately. Many unique combinations are thus possible

  4. Remember, the dominant gene masks the expression of the recessive one. Like we will see next

  5. Test cross  Sometimes you need to figure out the genotype of an individual.  You can do this by crossing it with a homozygous recessive individual.  See the image on the next page as an explanation ☺

  6. A test cross is used to determine if a parent is homozygous or heterozygous for a dominant trait. This is done by crossing it with a homozygous recessive individual and observing the results in the offspring.

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