Download Unit 2 Concepts Study Guide

Unit 2: How to Screen What Is In Your Genes
Lesson 1: Genetic Testing and Screening Concepts:
1. Genetic testing is the use of molecular methods to determine if someone has a genetic disorder, will
develop one, or is a carrier of a genetic illness and involves sampling a person’s DNA and examining
the chromosomes or genes for abnormalities.
o Amniocentesis: removal of amniotic fluid to examine free-floating fetal cells
o CVS: removal of cells from the placenta via catheter through vagina
o Carrier screening: look the see if an individual is heterozygous for a trait via electrophoresis.
o Karyotyping: picture of all the chromosomes in an individuals cells; look for abnormal number and
shapes.
2. Genetic counseling can help a family understand the risks of having a child with a genetic disorder,
the medical facts about an already diagnosed condition, and other information necessary for a person
or a couple to make decisions suitable to their cultural, religious and moral beliefs.
o Single gene disorders: mutation in a single gene on a specific chromosome.
o Chromosomal disorders: mutation in the entire chromosome; addition or deletion of a chromosome or
piece of a chromosome; viewed with karyotype.
o Multifactorial disorders: many factors (genetic and
environmental) contribute to this disorder.
o Mitochondrial disorders: diseases passed on nonchromosomal DNA from the mother to the child.
3. The polymerase chain reaction (PCR) is a laboratory
procedure that produces multiple copies of a specific DNA
sequence.
o Goal: amplify a DNA region or gene of interest.
o Denaturation: separate double stranded DNA; high
temperatures ~90C.
o Annealing: primers attached to the single stranded DNA at
specific targets; ~40C.
o Extension: free nucleotides (dNTPs) are added to extend
the new strands after the primer; ~60-70C.
o Components: Taq polymerase, primers, dNTPs, buffer.
o Taq Polymerase: found in bacteria in thermal springs –
used instead of human DNA polymerase due to high temps
4. Single base pair changes called single nucleotide polymorphisms (SNPs) can be identified through
genetic testing and often correlate to specific diseases or traits.
 SNPs and SNP profiles can be used to
o determine which allele a person carries for a particular gene
o determine how a person will react to a particular medicine
5. Proper prenatal care and monitoring of the fetus are vital to maternal
and child health during a pregnancy.
o Ultrasound: performed all pregnancy
o Monitor fetal size, heart rate,
structural abnormalities.
o CVS – Chorionic Villus Sampling:
performed between 10-14 weeks
o Takes sample of Chorionic Villi
cells
o Amniocentesis: performed between 13
– 20 weeks
o Takes sample of amniotic fluid
o Prenatal diet and lifestyle choices matter.
Lesson 2: Our Genetic Future Concepts:
1. Gene therapy is a type of disease treatment in which faulty genes are replaced by functional copies.
2. Various vectors, including viruses, can be used to transfer DNA into human cells.
o Adenovirus: infects diving and non-diving cells, can cause immune response.
o Retrovirus: only infects dividing cells, recognize specific proteins on a cell surface, can cause an
immune response.
o Liposome: not specific to any kind of cell, can be toxic.
o Naked DNA: works best with tissues that are superficial.
3. Both sperm sorting and embryo selection by preimplantation genetic diagnosis (PGD) provide
parents the option to select the gender and/or genetic characteristics of a child.
o Sperm sorting: separation of gametes based on weight. Female (XX) heavier, male (XY) lighter.
Followed by artificial insemination with selected sperm.
o PGD – Preimplantation Genetic Diagnosis: removal of one of the eight original cells of a specific
gender that is then implanted after in vitro fertilization.
4. Advances in reproductive technology open many moral, ethical, and scientific debates.