2.4.7 - Genetic Screening

Question 1

What Is Genetic Screening?

Answer 1

Analysing DNA to see if it contains alleles for genetic disorders.

Question 2

What Are The 3 Main Uses Of Genetic Screening?

Answer 2

~ Identification of carriers.

~ Preimplantation genetic diagnosis (PGD).

~ Prenatal testing.

Question 3

Describe ‘Identification Of Carriers’ As A Use Of Genetic Screening
(4 Points)

Answer 3

~ Offered to individuals with a history of genetic disorders in their family.

~ Can show whether people who have no symptoms carry the allele for particular disorders. E.g. Cystic fibrous.

~ Couples are able to be tested prior to having children to determine the probability of future inheriting the disorder.

~ Allows couples to make informed decisions before having children.

Question 4

Describe ‘Preimplantation Genetic Diagnosis’ As A Use Of Genetic Screening
(4 Points)

Answer 4

~ Carried out on embryos produced by in vitro fertilisation (IVF).

~ It involves analysis of the DNA of an embryo prior to being implanted into the uterus.

~ Reduces the chance of having a baby with a genetic disorder.

~ Avoids abortion as it is carried out before implantation of the embryo.

Question 5

Describe ‘Prenatal Testing’ As A Use Of Genetic Screening
(4 Points)

Answer 5

~ Offered to pregnant women with a family history of genetic disorders.

~ Involves testing the foetus for genetic diseases.

~ The DNA can be obtained by chronic villus sampling or amniocentesis of embryos or foetuses in the uterus.

~ Allows parents to make informed decisions and the results can help prepare parents for future care of the child.

Question 6

Describe ‘Chronic Villus Sampling’ As A Method Of Prenatal Testing, As A Use Of Genetic Screening
(4 Points)

Answer 6

~ Involves removing and testing a small sample of cells from the chronic villi using a fine needle.

~ The cells contain foetal DNA, which can be analysed for genetic disorders.

~ Carried out at around 11-14 weeks of pregnancy.

~ Has A 1-2% risk of miscarriage.

Question 7

Describe ‘Amniocentesis’ As A Method Of Prenatal Testing, As A Use Of Genetic Screening
(4 Points)

Answer 7

~ Involves removing and testing a small sample of cells from amniotic fluid, using a fine needle.

~ The fluid contains foetal cells, which contain DNA to be analysed.

~ Carried out at around 15-20 weeks of pregnancy.

~ Has a 1% risk of miscarriage.

Question 8

What Are The Social & Ethical Issues Of Using Identification Of Carriers?
(4 Points)

Answer 8

~ Finding out your a carrier can cause emotional stress or affect your ability to find a partner.

~ Other genetic disorders may be found, adding more emotional stress.

~ Employers and insurance companies may use the data against an individual.

~ Tests are not always 100% accurate, making decision making on wrong information.

Question 9

What Are The Social & Ethical Issues Of Using Preimplantation Genetic Diagnosis?
(2 Points)

Answer 9

~ Could lead to designer babies, where parents select embryos with certain traits.

~ False information could lead to poor decisions being made.

Question 10

What Are The Social & Ethical Issues Of Using Prenatal Testing?
(3 Points)

Answer 10

~ Each procedure brings a risk of miscarriage.

~ False information could lead to poor decisions being made.

~ There are ethical implications involved if parents deicide to abort the foetus.