How genetic screening is carried out in an adult human

  • samples of cells taken
  • e.g white blood cells
  • test for chromosomal abnormalities
  • e.g Down’s Syndrome
  • cells cultured so that they divide
  • stopped at metaphase
  • use of colchicines
  • cells made to take up water
  • chromosomes separated
  • karyotype produced
  • flourescent makers to help detect abnormalities
  • test for particular allele
  • DNA extracted
  • DNA cut with restriction enzyme
  • electrophoresis occurs
  • to separate DNA into strands
  • complementary/specific probe(for mutant allele)


The advantages of screening for genetic conditions

  • information about the increased risk of person having genetic conditions ;
  • ref. breast cancer/ named example ;
  • allows people to prepare for late onset genetic conditions ;
  • ref. Huntington’s disease/Alzheimer’s disease/named example ;
  • identify whether fetuses are going to develop a genetic condition ;
  • so can give early treatment when born ;
  • allows parents to prepare for the birth of a child who will need treatment for a considerable time or even throughout life ;
  • identifies carriers of genetic conditions ;
  • helps to provide early diagnosis ;
  • allows couples who are both carriers of a genetic condition to make decisions about starting a family/ having more children/ seeking IVF ;


The advantages and disadvantages of genetic screening in humans.

  • Advantages
    • known risk for next generation;
    • allows possible abortion of affected fetus;
    • allows sorting of IVF embryos;


  • Disadvantages
    • loss of hope;
    • insurance company problems;
    • employment problems;
    • miscarriage risk;
    • trauma of knowledge;

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