MI Unit 2

Amniocentesis

Amniocentesis

A technique for determining genetic abnormalities in a fetus bt the presence of certain chemicals or defectice fetal cells in the amniotic fluid, obtained bt aspiration from a needle inserted into the uterus.

Anneal

To be capable of combining with complementary nucleus acid by a process of heating and cooling.

Carrier screening

Indiscriminate examination of members of a population to detect heterozygotes for serious disorders.

Chorionic villus sampling (CVS)

A technique for diagnosing genetic and congenital defects in a fetus by removing and analyzing a sample of the fetal portion of the placenta.

Denaturation

In DNA, the separation of two strands of the double helix.

Gene

A discrete unit of heredity information consisting of a specific nucleotide sequence of DNA.

Genetic counseling

A process of communication that deals with the occurrence or risk that a genetic disorder will occur in a family.

Genetic testing

The use of methods to determine if someone has a genetic disorder, will develop one, or is a carrier.

Genome

The complement of an organism's genes; an organisms genetic material.

Genotype

The genetic makeup of an organism.

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

Newborn screening

The analysis of a neonate's blood for metabolic or genetic disorders to prevent mental retardation, disability or death.

Phenotype

The physical and physiological traits of an organism.

Polymerase chain reaction (PCR)

A technique that involves copying short pieces of DNA and then making millions of copies in a short period of time.

Preimplantation Genetic Diagnosis (PGD)

In assisted reproductive technology, the determination of genetic abnormalities in the embryo before it is transferred to the uterus.

Primer

A short piece of DNA or RNA that is complementary to a section of template strand and acts as an attachment and starting point for the synthesis strand during DNA replication.

Restriction enzyme

A degradation enzyme that recognizes specific nucleotide sequences and cuts up DNA.

Single nucleotide polymorphism (SNP)

One base-pair variation in the genome sequence.

Supernatant

The (usually) clear liquid left behind after a precipitate has been spun down to the bottom of a vessel by centrifugation.

Taq polymerase

A DNA synthesis enzyme that can withstand the high temperatures of PCR.

Thermal cycler

An instrument that automatically cycles through different temperatures used to complete PCR reactions.

Ultrasonography

A noninvasive technique involving the formation of a two-dimensional image used for the examination and measurement of internal body structures and the detection of bodily abnormalities.

What percent of everyone's genome is the same?

99%

Duchenne Muscular Dystrophy

Progressive muscle degeneration and weakness

• Poor weight gain and growth

• Intestinal blockage, particularly in newborns (meconium ileus)

• Severe constipation

Huntington's Disease

Single gene dominant disorder

• nerve cells in certain parts of the brain waste away, or degenerate

• genetic defect on chromosome 4

• the defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with ... disease, it is repeated 36 to 120 times.

• The most common is adult-onset ... disease. Persons with this form usually develop symptoms in their mid-30s and 40s.

• An early-onset form of ... disease accounts for a small number of cases and begins in childhood or adolescence.

Symptoms

• Behavioral disturbances

• Hallucinations

• Irritability

• Moodiness

• Restlessness or fidgeting

• Paranoia

• Psychosis

• Facial movements, including grimaces

• Head turning to shift eye position

• Quick, sudden, sometimes wild jerking movements of the arms, legs, face, and other body parts

• Slow, uncontrolled movements

• Unsteady gait

• Disorientation or confusion

• Loss of judgment

• Loss of memory

• Personality changes

• Speech changes

Down Syndrome

• genetic disorder that causes lifelong mental retardation, developmental delays and other problems

• Chromosomal disorder

Symptoms

• Flattened facial features

• Small head

• Short neck

• Protruding tongue

• Upward slanting eyes, unusual for the child's ethnic group

• Unusually shaped ears

• Poor muscle tone

• Broad, short hands with a single crease in the palm

• Relatively short fingers

• Excessive flexibility

Leber hereditary optic neuropathy

• Mitochondrial disorder

• Inherited form of vision loss

• Males affected more than females

• Movement disorders

• affects 1 in 30,000 to 50,000 people in northeast England and Finland.

• features similar to multiple sclerosis, which is a chronic disorder characterized by muscle weakness, poor coordination, numbness, and a variety of other health problems

• mitochondrial pattern of inheritance, which is also known as maternal inheritance

Alzheimer's disease

• Multifactorial disorder

• an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks

• as many as 5.1 million Americans may have ... disease

• most common cause of dementia

How would a genetic counselor use a pedigree to help his or her clients understand genetics?

Pedigrees show the route in which genetic diseases take as far as the inheritance in involved. A genetic counselor would use a pedigree to show the inheritance of a certain genetic disease/disorder in a particular family.

Compare and contrast preimplantation genetic diagnosis and fetal testing. Does one type of test raise more ethical concerns than the other? Explain your thinking.

Preimplantation genetic diagnosis: used by people with autosomal dominant conditions who don't want to pass it on to the child

Fetal testing: performed on fetuses still in the uterus

Both: raise concer

Fetal screening raises ethical concerns because you are working on the fetus and preimplantation raises concern because ''designer babies''

Explain why parents may be fearful or apprehensive about genetic testing.

they are told everything that MAY go wrong with the baby and freak out over things that might not even happens.

How might factors such as income and access to medical insurance, influence a couple's genetic testing and reproductive decisions?

Some parents may be afraid to find out if their child has a genetic disease/disorder before he/she is born. It could put a good amount of stress on both parents during the pregnancy.

Why are studies of identical twins raised in different environments extreme valuable in understanding the cause of a disease?

Depending on the study and the particular trait of interest, data is collected and compared from identical or fraternal twins who have been raised together or apart. Finding similarities and differences between these sets of twins is the start to determining the degree to which nature and environment play a role in the trait of interest.

Recall the molecular tools you studied in PBS and HBS- Gel electrophoresis, PCR, and restriction analysis. How do you think these techniques and procedures can be used to test human genes?

What plays a role in the development of disease?

Environmental and genetic factors.

4 types of genetic disorders:

Single-gene

Multifactorial

Chromosomal

Mitochondrial

Single-gene

Changes or mutations that occur in the DNA sequence of ONE GENE

What does a gene contain?

Instructions for the production of a protein.

Single gene can be inherited in..

Autosomal dominant

Autosomal recessive

Sex linked

A man and a women are both carriers for sickle cell disease, an autosomal recessive trait. What is the risk of their having an affected child?

25% since each parent is heterozygous

Multifactorial disorders

Combination of environmental factors and mutations in multiple genes. (Heart disease and breast cancer) ( many are most common chronic illnesses)

Chromosomal disorders

-46 chromosomes

-44 autosomes( body)

-2 sex

Karyotypes diagnosis chromosomal disorders