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Genetic Variation (What is Sickle cell? (Recessive trait (Parents must be…
Genetic Variation
What is Sickle cell?
Misshapen blood cells due to atypical haemoglobin
Recessive trait
Parents must be Carriers
Heterozygous the disease
co-dominant
red blood cells shape and resistance to malaria
It is Germline
Caused by a mutation
in haemoglobin -> haemoglobin S
Causes of Genetic Variation
Mutation
during meiosis
During mitosis
Random mating
Random fertilisation
Genetic technologies
PCR The polymerase chain reaction
Developed in 1983 by the American biochemist Kary Mullis
Uses
identify pathogens during infection
Generating forensic DNA profiles from tiny samples of DNA
How
Five cores are required to set it up
DNA template to be copied
Primers; bind DNA to be copied
DNA nucleotide bases make a new strand
Taq polymerase enzyme to add in the new DNA bases
Buffer for the right conditions
Table from:
https://www.yourgenome.org/facts/what-is-pcr-polymerase-chain-reaction
Cytochrome Oxidase 1
ideal for extraction and replication
found in mitochondria (in DNA)
many copies of the gene
No variations
Taq polymerase
suited to hotter temperatures
can be denatured and replicated
Electrophoresis
Freeing DNA from the nucleus in each cell
Tissue matric of each cell
Cell and nuclear membranes to access DNA
The proteins bound to the DNA
Molecular markers identifiy of protected species
DNA travels in gel - electric current is applied
DNA is negatively charged
Larger pieces or DNA will lag behind
(separates base pairs)
combined in fluorescent to see bands
Uses
DNA fingerprinting
Identifying species
Classifying organisms
Steps
Making the gel Agarose
Measuring the size of the fragments
Loading the wells
Viewing the DNA and comparing
Other technologies
sound waves to measure blood flow
A blood test can check for Haemoglobin
Before birth checking the fluid
amniotic fluid
blood transfusions
Minimize stroke risk
How (process) / Where sickle Cell occurs
It occurs during Meiosis
It is a Germ line and point mutation
Parents either heterozygous, or homozygour
Types of Mutations
Table from:
https://www.nature.com/scitable/topicpage/genetic-mutation-441/
Somatic Mutation
Occurs in non-reproductive cells
Localized effects
Spontaneous mutations
Often due to replication failures
Germline Mutation
occurs in sexual reproductive cells
Passed onto offspring
Entire organism carries mutation and half of gametes
Mutation gamete + non gamete -> embryo
Mutation replicated in every cell in an organism
What are the effects of Sickle
Atypical haemoglobin molecules distort red blood cells into a crescent shape
Painful episodes can occur
Abnormal protein in the red blood cells
Effects on genetic diseases on humans
Groups of people
African
20-40% higher
Hispanic background
Malaria
heterogeneous - resistance
A.C. Allison theory about Malaria resistence
Doesn't protect against infection but progression on Malaria
A blood disease caused by mosquitoes
Prominent in African groups
Adapted resistence
Benefits of research
Cures
A blood and bone marrow transplant
only small no. of people
only cure for sickle cell disease
rejection-> life threatening complications
Immunizations (penicillin) prevents infection
Hydroxyurea = cells less sticky.
Blood transfusions
Linus Pauling
Collected haemoglobin from sickle cell anaemia
based on electrophoretic mobility patterns