BIOLOGY
GENETICS INC. DISEASE AND STEM CELLS
- Created by: Ella Ronan
- Created on: 19-01-13 18:06
POLYDACTYLISM
-CAUSED BY A DOMINANT GENE / ALLELE
-CAN BE INHERITED FROM ONE PARENT
- P = Polydactylism (DOMINANT)
- p = normal (RECESSIVE)
EG
MUM = pp (HOMOZYGOUS RECESSIVE)
DAD = Pp (HETEROZYGOUS)
PUNNETT SQUARE HERE:
50% CHANCE CHILD IS NORMAL
50% CHANCE CHILD IS POLYDACTILE
CYSTIC FIBROSIS
-AFFECTS THE LUNGS AND PANCREAS
-ORGANS (INCLUDING REPRODUCTIVE SYSTEM) ARE CLOGGED UP BY A THICK STICKY MUCAS
-CF IS CAUSED BY A RECESSIVE ALLELE FROM BOTH PARENTS
C = DOMINANT c = RECESSIVE
PUNNETT SQUARE HERE:
PARENTS ARE KNOWN AS CARRIERS
IF BOTH PARENTS ARE HETEROZYGOUS, OFFSPRING DOES NOT HAVE CF
One in 25 carry the CF gene in the UK, but most people are unaware.
HUNTINGTON'S DISEASE
-CAUSED BY ONE DOMINANT GENE
-CAUSES DEATH AT MIDDLE AGE
H = HUNTINGTONS h = NO HUNTINGTONS
MUM = hh DAD = Hh
PUNNETT SQUARE HERE:
50% CHANCE OF INHERITING DISEASE
SCREENING FOR GENETIC DISEASES PROS/CONS
FOR
- 'Healthier' humans
- Would not want children to suffer
- Could prepare yourself
- May not want to pass onto offspring
- Able to live life to the fullest
AGAINST
- Unethical - embryo's have not given consent
- Religious beliefs - life starts at conception and is sacred
- Screening is expensive
- Would not want to worry that your children had the disease
CURING GENETIC DISEASES
- NO WAY AT THE MOMENT OF CURING GENETIC DISORDERS BUT THOUGHTS THAT GENETIC ENGINEERING COULD HELP
- TRIED CUTTING OUT FAULTY ALLELES AND REPLACING THEM WITH HEALTHY ONES IN PEOPLE WITH CF BUT SO FAR IT HASN'T CURED ANYONE
- IT IS POSSIBLE TO SCREEN DURING PREGNANCY OR IVF FOR INHERITED GENETIC DISEASES HOWEVER THIS RAISES MANY ETHICAL ISSUES, ESPECIALLY IF AFTER TESTING PEOPLE CHOOSE WHETHER OR NOT TO HAVE A FAMILY
THE FUTURE OF STEM CELL RESEARCH
- Some ethical concerns have been removed after the discovery of umbilical cord blood containing stem cells
- Therapeutic cloning could be very useful but is proving very difficult
- this involves using cells from an adult to produce a cloned early embryo of themselves.
- There are hopes that stem cells will change medicine in the future
ADVANTAGES: - can help diseases by growing new organs when needed, help save lives
DISADVANTAGES: - ethical issues, slow progress, unaware of potential problems that could occur, religious issues, expensive to set up labs/equipment
STEM CELLS
-UNSPECIALISED CELLS
-THAT CAN DIFFERENCIATE INTO MANY DIFFERENT TYPES OF CELL WHEN NEEDED
-FOUND IN EMBRYOS AND ADULT BONE MARROW AND UMBILICAL CORD BLOOD
-THE EMBRYO FORMS A HOLLOW BALL OF CELLS AND THE INNER CELLS OF THIS BALL ARE THE STEM CELLS
-POSSIBLITY OF GROWING ACTUALY ORGANS IN THE FUTURE
-ADULTS HAVE SOME STEM CELLS REMAINING IN THEIR BONE MARROW, BRAIN, OVARIES ETC
-THEY ARE ONLY NEEDED IF TISSUE IS DAMAGED / INJURED / DISEASED
-SCIENTISTS US THEM TO REPAIR SPINAL CORDS, HEART VALVES, INSULIN PRODUCING CELL (DIABETICS)
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