Q 1- What is the name of the genetic technique that would help a person who inhe
ID: 99912 • Letter: Q
Question
Q 1- What is the name of the genetic technique that would help a person who inherited Li Fraumeni Syndrome(autosomal dominant) genetic disorder to have a child without the defective allele?
Q 2- In order to test Lee for a genetic disorder (Li Fraumeni Syndrome), Dr. Aikenhed will probably take a sample of cells containing his genomic DNA by swabbing his cheek or taking a blood sample. Why is it important to use non-cancerous cells to test Lee for a genetic disorder instead of the biopsy tissue?
Q 3- Describe the main technique for amplifying a segment of DNA (Lee’s cancer) from a complex mixture of genomic DNA. Remember that the entire human genome sequence is known.
Q 4- If Dr. Aikenhed wanted to see if there was mutation within the protein-coding sequence of the gene implicated in Li Fraumeni disorder (as opposed to mutations affecting regulatory elements), what technique involving dideoxynucleotides could be used? Briefly describe this technique.
Explanation / Answer
1. Preimplantation genetic diagnosis (PGD) is a medical procedure done in conjunction with in-vitro fertilization (IVF). It allows people who carry a specific known genetic mutation to have children who do not carry the mutation. A woman’s eggs are removed and fertilized in a laboratory. When the embryos reach a certain size, 1 cell is removed and is tested for the hereditary condition in question. The parents can then choose to transfer embryos that do not have the mutation. PGD has been in use for over 2 decades, and has been used for several hereditary cancer predisposition syndromes. However, this is a complex procedure with financial, physical, and emotional factors to consider before starting.
2.Cancer cells in the biopsy contains many other genetic mutations hence non cancerous cells are used to detect a genetic disorder for this syndrome.
3.Polymerase chain reaction is the technique which is a kind of "molecular photocopying" the required DNA sequences among the entire genome and thus amplifying it.
To amplify a segment of DNA using PCR, the sample is first heated so the DNA denatures, or separates into two pieces of single-stranded DNA. Next, an enzyme called "Taq polymerase" synthesizes - builds - two new strands of DNA, using the original strands as templates. This process results in the duplication of the original DNA, with each of the new molecules containing one old and one new strand of DNA. Then each of these strands can be used to create two new copies, and so on, and so on. The cycle of denaturing and synthesizing new DNA is repeated as many as 30 or 40 times, leading to more than one billion exact copies of the original DNA segment.
4.Microarray technique.
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