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  • Genetic Disorders
    • Some disorders that are inherited such as..
      • Red-green colour blindness
      • Sickle cell anaemia
      • Cystic fibrosis
      • Inherited disorders are caused by faulty genes, which are mostly recessive alleles. For example cystic fibrosis is an inherited disorder that affects the cell membranes causing the production of thick and sticky mucus.
        • It is caused by a recessive allele, which means that it is inherited from both parents.
    • Genetic testing
      • Scientists are now able to test adults and unborn babies for alleles that can cause genetic disorders.
      • However the scientific information produced raises many issues that science cannot address. For example, should a couple with one in four risk of having a child with cystic fibrosis take the gamble or not have children at all?
      • Genetic diagrams are used to show the possible outcomes of a particular cross.
      • A dominant allele is shown by a capital leter and a recessive allele by a lower case letter.
    • Cystic Fibrosis
      • This is an inherited disorder caused by a recessive allele. This gentic diagram shows the positive outcomes when both parents are heterozygous for the faulty allele
        • There is one in four chance of the offspring being homozygous for the faulty allele, and so having cystic fibrosis


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