mi unit 2

karotype

A picture of all the chromosomes in a cell arranged in pairs

Pedigree

A chart or "family tree" that tracks which members of a family have a particular trait

affected pedigree

is shaded/colored

Carrier in pedigree

Half-Shade

Unaffected pedigree

unshaded

multifactorial

determined by many factors, both genetic and environmental, collectively influence phenotype

Diabetes, Dementia, High Blood Pressure are types of what disorders

multifactorial disorders

single gene

change or mutation in one gene

single gene recessive trait examples

sickle cell and cystic fibrosis

single gene dominant trati examples

dwarfism and huntington's disease

sex-linked trait

passed on the sex chromosomes (the X or the Y)

why do males more affected by sex linked trait diseases?

because women have 2 X chromosomes and only need one to function while men have only 1 X-chromosome

mitochondrial disorders

Leber's heditatry optic nueropathy

sex linked trait examples

colorblindness, duchenne muscular dystrophy and hemophilia

what disorder is only passed from mother to child?

mitochondrial disorders

chromosomal disorders

not having enough or having extra chromosomes

what are some examples of chromosomal disorders?

Down Syndrome, Turner's Syndrome, Klinefelter's Syndrome

how are chromosomal disorders revealed?

karotypes

what do we use to find out abt diseases?

genetic screening

Carrier Screening

test that is typically done on adult couples who are considering having children and want to determine if those children could inherit any diseases.

how is carrier screening done?

blood sample is drawn, DNA is extracted and amplified using PCR, and then DNA goes under testing for diseases.

Preimplantation Genetic Diagnosis (PGD)

often used by people with known autosomal dominant or sex-linked conditions that they do not want to pass on to their children

How is PGD done?

eggs are fertilized in a vitro dish and after they are developed, a single cell from each embryo is removed, amplified, and tested for the trait the parents dont want to pass

Fetal Screening/Prenatal diagnosis is performed when?

when fetuses are inside the mommy

amniocentesis

needle puncture of the amniotic sac to withdraw amniotic fluid for analysis

When is amniocentesis performed?

14-20 weeks

chorionic villus sampling

the examination of cells retrieved from the placenta

what are risks of getting amniocentesis chorionic villus sampling?

miscarriage

Newborn screening

the testing of infants shortly after birth

how do we do newborn screening?

A small sample of blood is taken from the baby, and DNA is isolated from it for testing purposes

Newborn screening is used for what?

for inherited diseases if the parents choose not to implement measures that complete this testing while the baby is still in utero

What does PCR stand for

polymerase chain reaction

What do we use for PCR?

taq polymerse, DNA primers, and DNA nucleotides

what is the first step of PCR

denaturation

what is denaturation

high temperature breaks hydrogen bonds that hold the double stranded DNA together.

Second step of PCR

annealing

what is annealing

dna primers are added to the dna mixture and dna primers are binding to dna

why is dna primer present?

so taht the DNA is reading for copying

what is the 3rd step of PCR

extension

what is extension?

taq polymerse is used to copy bacterial dna before bacterial cells divide.

what is genotype

genetic code for traits that we possess

testing for traits in the lab can be done with what?

gel electrophoresis

what does centrifugation do?

separates DNA from cell waste

why are restriction enzymes used for gel electrophoresis for gene testing?

so that different versions of the gene, "bad" or "good", can be distinguished

what does the end result of gel electrophoresis determine?

reveals the genotype of the individual being tested

what trimester is critical during pregnancy?

the first

what is gene therapy?

the transplantation of normal genes into cells in place of missing or defective ones in order to correct genetic disorders.

what are vectors

viruses

type of vectors?

retroviruses, adenoviruses, adeno-associated viruses, herpes simplex viruses, liposomes, and naked DNA.

purpose of vectors?

providing unaffected genes to people carrying specific genes

sperm sorting

a method of separating sperm that carry Y chromosomes from sperm that carry X chromosomes; you can choose gender of the baby

plasmid and liposome

-can be any size
-dna
-dont generate immune response
-dont do genome integration
-less efficient, therefore result in low protein levels

Herpes virus

-dna
-double stranded
-only infects nervous cells
-creates immune response

adenovirus

-dna
-double stranded
-can enter differing cell types
-creates immune response
-results in high levels of protein

Retrovirus

-rna
-only infects dividing cells
-creates immune response
-integrate with genes randomly

Adeno-associated virus

-dna
-single stranded
-can enter different amount of cells
-create permanent genome integration

Lentivirus

-rna
-can enter different types of cells
-integrates with genes randomly

Cystic Firbrosis

an inherited disease that affects glands, causing buildup of mucus, which blocks the ducts

cystic fibrosis means a lack of what?

CFTR gene which controls salt and balance of water in the body

what vector should be used for cystic fibrosis?

adeno-associated

which screening method removes cells from the placenta?

chronic villus sampling

which method removes amniotic fluid for testing?

amniocentesis

which screening method is the least risky/invasive

ultrasound

a single cell is taken from an embryo and tested for genetic abnormalities. what method was used?

pre-implantation genetic diagnosis (PGD)

which disorder is caused by an extra chromosome

down syndrome

which disorder is considered to be multifactorial

alzeheimer’s disease

what is not a step in PCR

sequencing

what causes DNA fragments to separate in each lane of an agase gel?

electrical current

dna fragments separate during gel electrophoresis according to their…

size

what are the correct pcr steps

denaturation, annealing, extension

what type of genetic disorder is the best target for gene therapy?

single gene mutation

which is not an important consideration when choosing a gene therapy vector

whether its RNA or DNA

which 2 techniques can be used to select the sex of the baby

sperm sortinga and PGD

what kind of genetic disorder is down syndrome

chromosomal

what kind of genetic disorder is cystic fibrosis

single gene recessive

what pre-natal screening/testing can be done earlier during pregancy

CVS

which gene therapy vector carries single stranded rna

retrovirus

what gene vector would be ideal for inserting a gene that was 18500 base pairs long

herpes-simplex virus

what kind of genetic disorder can be detected with a SNP analysis and gel electrophoresis?

single gene

what genetic disorder can be detected with a karotype

chromosomal

which occur when gametes are fertilized in a dish in the lab which result in a zygote

IVF