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Genetic Diversity
The amount of genetic variation that exists between individuals.
Measured by reference to a population’s gene pool
Gene Pool
The sum of all the different alleles in a population
Diverse gene pool = Greater variety of genotypes and phenotypes (genetic diversity)
Examples of Environmental Changes
New predator species, temperature changes, new diseases
Importance of High Genetic Diversity
Populations with a greater genetic diversity (number of alleles in gene pool) are more likely to have alleles that are already well adapted to survive new environmental challenges
Therefore, the larger the gene pool, the greater that population's resilience to environmental change.
Disadvantages of Low Genetic Diversity
Reduced adaptability to adverse environmental conditions due to the lack of different alleles in a gene pool, which makes a population more likely to enter extinction
Increased susceptibility to disease
Sexual Reproduction (Definition and what it entails)
Involves the contribution of genetic material from two parents
Two haploid gametes fuse, via fertilisation, to form a genetically unique organism
Examples of Sexual Reproduction
Oviparity
When eggs are laid by the female and the embryo develops outside of the mother’s body (Egg hatching)
Ex. Snakes
Vivaparity
When the embryo develops within the mother’s body (Live-bearing)
Ex. Humans
Angiosperms
Plants that fertilise via pollination
Ex. Daffodils
Advantages of Sexual Reproduction
Increases genetic diversity of a population by allowing for recombinant, genetically unique offspring
Improves resistance to environmental changes by promoting the presence of different allele combinations
Reduces the risk of offspring inheriting a genetic disorder that might be carried by one parent.
Disadvantages if Sexual Reproduction
Requires time
Requires lots of energy and resources
Requires a mate/partner
Risk of losing offspring to outside influences such as embryo damage
Asexual Reproduction
Offspring formed from a single parent.
The offspring is a clone of the parent (genetically identical to one another)
Examples of Asexual Reproduction
Vegetative Propagation
Fragmentation
Budding
Binary Fission
Advantages of Asexual Reproduction
Populations grow exponentially fast in comparison to sexually reproducing animals (Reproduce faster)
Organisms that have adapted a phenotype that is fined tuned to survive in a particular environment are all identical
Does not require a mate to reproduce, and therefore the organism does not need to be mobile
Requires very little parental investment/energy
Removes the need to protect fragile offspring
Disadvantages of Asexual Reproduction
Low genetic diversity and therefore higher susceptibility to being wiped out by a new environmental change
Difference between sexual and asexual reproduction
Sexual
Involves the contribution of genetic material from 2 parents
Offspring is genetically unique
Asexual
Involves the contribution of genetic material from 1 parent
Offspring is genetically identical (clone) to the parent
Clone
Genetically identical organisms
Somatic Cell
A body cell other than a sex cell
Diploid (2n)
Ex. Skin cell
Haploid
Describes a single set of chromosomes in a cell
Noted by n
Only found in gametes
Diploid
Describes two sets of chromosomes in a cell (one from each parent)
Somatic cells
How are offspring produced via sexual reproduction genetically unique?
Due to the mixing of genetic material from two parents during fertilisation, which leads to a unique combination of genes in the offspring. The gametes used in fertilisation contain a single set of chromosomes and are a unique combination of genes (Unique genetic make-up) due to the exchange of maternal and paternal alleles during independent assortment and crossing over in meiosis.
Nucleus
A cell organelle that contains genetic information (DNA) and controls cellular functions
Stem Cell
Undifferentiated cell with the capability of differentiating into specialised body cells
Cloning
Process of creating a genetically identical copy of an organism
SCNT
Somatic Cell Nuclear Transfer
Process of cloning an organism by transferring the nucleus of a somatic cell into an enucleated egg cell
Steps in the SCNT Process
Step 1 : Enucleation
The removal of a haploid nucleus from a donated egg cell, producing an enucleated egg
Step 2 : Extraction
The diploid nucleus of a donated somatic cell is extracted
Step 3: Insertion
The diploid nucleus of the donated somatic cell is inserted into the enucleated egg cell
Step 4: Development
The egg is implanted into the uterus of a surrogate mother and the pregnancy continues as normal. The surrogate will give birth to a clone of the somatic cell donor
Benefits of Cloning in Agriculture
Can involve both crops and livestock
Slow growing plants can be produced in large numbers
Organisms can be produced year-round
Organisms with desirable traits can be produced
(eg. Disease resistant plants or low fat milk)
Disadvantages of Cloning in Agriculture
No genetic variation in offspring, therefore decreased ability to adapt to environmental conditions
Disease can spread rapidly through crops and wipe them out quickly
Bioethical Considerations Regarding SCNT Cloning
Very high failure rate
May be due to insufficient nuclear programming as the donor nucleus goes from directing an adult somatic cell to directing a new embryo
Very expensive (hundreds of thousands of dollars)
Therapeutic Cloning
Involves the cloning of particular tissues for medical benefit in humans
2 type of stem cells
Embryonic and Adult
Embryonic Stem Cells
Stem cells that come from a human embryo and are pluripotent, meaning that they can differentiate into almost any cell type
Adult Stem Cells
Stem cells that come from bone marrow and are multipotent, meaning that they can only differentiate into a limited number of specialised cells
Totipotent Vs Pluripotent Vs Multipotent
Totipotent - Can differentiate into any cell type
Pluripotent - Can differentiate into almost any cell type
Multipotent - Can differentiate into a limited number of cell types
Process of Extracting Embryonic Stem Cells
Follows process of SCNT
Instead of implanting the embryo into the uterus of a surrogate mother, the embryonic stem cells are harvested and grown (cultured) in a lab.
After harvest, the embryonic stem cells are forced to differentiate into the cell type required for treatment
Why are embryonic stem cells better than adult stem cells?
No tissue rejection
Since the cell is created using the patient’s own DNA, it does not cause tissue rejection because the antigens on the cell surface match the patients cells which does not trigger an immune response
Advantages of Therapeutic Cloning
Replacement for conventional medical treatments such as organ transplants an d skin grafts
Can treat previously untreatable diseases
Disadvantages of Therapeutic Cloning
Low success rate during the creation of an embryo
Very expensive treatment which could require multiple rounds/trials
Bioethical Issues Regarding Therapeutic Cloning
Can be considered as “playing with God”
Concerns raised by religious/moral groups around the creation and destruction of an embryo. Doubts about the “status” of the embryo” as a potential life.
Very expensive
What are the “Ethical Approaches”
Consequences-based approach
Duty/Rules-based approach
Virtues-based approach
Consequences-Based Approach
Whereby the right action is the one which leads to the best overall consequences or outcome for all.
Which action produces the most good and least harm?
Duty/Rules-Based Approach
Whereby people have an obligation to follow moral rules (duties) or guidelines (rules) and choose the right action that aligns with their responsibilities, even if it leads to negative consequences.
Which action is considered morally right, regardless of the consequences?
Virtues-Based Approach
Refers to taking action which practices integrity, honesty, courage, compassion and fairness (good morals), which allows to lead a good life
What action would a good person choose? FEELINGS BASED
What are the “Ethical Concepts”
Integrity
Justice
Beneficence
Non-maleficence
Respect
Integrity as an ethical concept
Refers to being honest, trustworthy and keeping your word
What is the honest action?
Do any promises need to be kept?
Is trust being maintained?
What is the conduct (behaviours/intentions) of the stakeholders involved?
Is there any misinformation involved?
Justice as an ethical concept
Refers to the equal distribution of benefits, risks, costs and resources to all stakeholders
Does everyone have access to the benefits of the action?
Do any stakeholders have an unfair burden?
Have all stakeholders and their opinions been recognised?
Beneficence as an ethical concept
Refers to aiming to improve the conditions of others through generosity, charity and kindness
What action maximises benefits and minimises harm?
How does the action help the stakeholders?
Non-maleficence as an ethical concept
Refers to avoiding actions which lead to harmful consequences
What are the risks?
What action does the least harm?
Can harm be avoided?
What action is the safest?
Respect as an ethical concept
Refers to the consideration of the wellbeing, freedom, independence, values and beliefs of all people
What do other people think/feel/need?
What action interferes the least with the differing views of others?
How can impact on other peoples needs/autonomy be accounted for?
What are the factors which influence bioethical issues?
Social factors
Economic factors
Legal factors
Political factors
Social Factors (Definition + Examples)
Factors that affect people’s lifestyle and wellbeing
Ex.
Confidentiality/privacy
Discrimination
Access to benefits
Impact on industry and livelihoods
Economic Factors (Definition + Examples)
Factors that can affect an individual’s financial status
Ex.
Cost of services/treatments
Access to healthcare
Legal Factors (Definition + Examples)
Factors that relate to laws, regulation and guidelines
Ex.
Intellectual property rights
Use of living organisms
Regulatory oversight
Consent
Political Factors
Refers to government-related influences on the strategies of businesses and organisations
Ex.
Legislation and policies on health and technology
Differing opinions and views
More specifically, abortion and assisted suicide laws, resource/funding allocation in healthcare,