565-W109 Part 2




Gametogenesis,the production of sperm and eggs, takes place through the process ofmeiosis. During meiosis, two cell divisions separate the pairedchromosomes in the nucleus and then separate the chromatids that weremade during an earlier stage of the cell`s life cycle, resulting ingametes that each contains half the number of chromosomes as theparent. The production of sperm is called spermatogenesis and theproduction of eggs is called oogenesis. This explains why Suzanne’schances of carrying the mutated APP gene is at 50% since duringmeiosis, there was a splitting up of the cells into two equalportions.


DNA(Deoxyribonucleic acid) is a self-replicating material present innearly all living organisms as the main constituent of chromosomes.It is the carrier of genetic information. It can also be described asthe fundamental and distinctive characteristics or qualities ofsomeone or something, especially when regarded as unchangeable.


Mutationsthat affect proteins that are necessary for life will result in thedeath of the organism just like the APP gene mutation. The mutationswithin these three genes PS1, PS2 and APP affect a common pathogenicpathway in APP synthesis and proteolysis leading to excessiveproduction of amyloid Beta. Genes and their associated proteins areshow below

APP– amyloid precursor protein which responsible for the regulation ofsynapses in the brain

PS1– Presenilin 1 which is important in proteolytic process in thebrain

PS2-Presenilin 2 which is responsible for processing amyloid precursorprotein, which is found in the brain and other tissues.


DNAis the blueprint that every living thing has. When DNA is changed, itis a change to the blue print, which when followed will now result ina change to the final product (a mutation). If the mutation resultsin a viable organism, it lives. If the mutation actually enhances theviability of the organism, it can become the dominate form of thatorganism. Mutations can be caused by simple random chance, or thechances can be increased through external stimuli’s (exposure tocatalysts, such as x-rays, certain chemicals). Some mutations aredominant and they will show the mutation through every successivegeneration. While if you have a recessive mutation, then thephenotype expressing the mutation could skip a generation.


HGPis an international scientific research project which is gearedtowards determination of the sequence of chemical base pairs whichmake up human DNA and the identification of mapping of all the genesof the human genome. HGP main objective is to analyze human genomecomposition and offer crucial advice to families at the same timecoming up with potential solutions to genetic disorders. The projectwas successive because it is through the initiative that Suzanne gotto know her genetic composition.


Beforeany test is done normally a doctor has to carry out a backgroundcheck on a patient and ensure that they understand what hereditarydisease they are testing. After which the patient is sent to agenetic counselor. It is after that, that the DNA of a patient iscollected and sent to the laboratory for testing. Figure 3 connotesone of the most employed techniques. PCR is a method of amplifying asmall amount of DNA to a larger amount so that it can be analyzedclosely. The genetic code of the DNA can be determined by a methodcalled ‘DNA sequencing’.


Thecouple has to prepare for negative ramifications because, Alzheimer’sdoes not encompass any cure and secondly it will definitely be passedon to the next generation. This means that chances are that they willsire children who are careers of the disease hence affected since itdoes not require double gene composition (autosomal).


Thecouple finds itself in a dilemma since there is a likelihood of themcreating a generation which is equally affected. A number of ethicalissues arise in the scenario, this include should the information berevealed if no cure exists, there exists undesired options aftertesting this depicts that the couple can no longer desire to getchildren, false positive and false negative results, uncertainimplications of early intervention and potential adverse personal aswell as societal consequences.



IVFis the process of fertilization by manually combining an egg andsperm in a laboratory dish, and then transferring the embryo to theuterus. The procedure does not carry immense risks since it isscientifically analyzed for possible faults. The steps to accomplishthis include

  • Monitor and stimulate the development of healthy egg(s) in the ovaries.

  • Collect the eggs.

  • Secure the sperm.

  • Combine the eggs and sperm together in the laboratory and provide the appropriate environment for fertilization and early embryo growth.

  • Transfer embryos into the uterus.


IVFis on most occasions used by parents with genetic disorders to allowthem to give forth healthy offspring’s. IVF is quite expensive andit requires people who can afford to undertake the procedurehowever, the insurance sector has come forth to address the costrelated problem by paying for all the attempts that may be required.


Eggdonors can suffer serious side effects from the powerful hormonesneeded to generate multiple eggs. The most significant risk isovarian hyper-stimulation syndrome, which can cause bloating,abdominal pain and, rarely, blood clots, kidney failure and otherlife-threatening ailments. Men only encompass minimal risks like risksecond thoughts about unknown, random offspring, but they do not riskserious medical side effects. The main drive that pushes people tocontinue with IVR is the desire to want children.


Sinceits inception in human lives IVF has been a point of contention interms of moral, ethical and religious underpinnings in the society.The Catholic Church has been on the front in opposing IVF doctrine onthree major grounds 1) the destruction of human embryos not used forimplantation 2) possibility of in vitro fertilization by a donorother than the husband hence removal of reproduction from the maritalcontext and 3) severing of an essential connection between theconjugal act and procreation. Other ethical questions raised includethe unusually high rate of multiple births associated with IVF. IVFhas also raised a number of unresolved moral issues concerning thefreezing (cryopreservation) of ovaries, eggs, sperm, or embryos forfuture pregnancies. Just like screening for diseases raises ethicalquestions, also child sex screening raises ethical issues.