Genetics

Define DNA:

Is the genetic material that contains genetic information and is composed of genes.

Define Gene:

carries directions for proteins and enzymes.

Define RNA:

arises from transcribed DNA and carries the directions and needed amino acids to build proteins.

Define Genotype:

the genetic makeup of an individual.

Define Phenotype:

the observable characteristics or traits of an individual.

Define Homozygous:

having two identical alleles for a gene.

Define Heterozygous:

having two different alleles for a gene.

Define Dominant:

an allele that is expressed when present.

Define Recessive:

an allele that is expressed only when two copies are present.

Define Autosomal Dominant:

a disorder caused by a dominant gene located on an autosome.

Define Autosomal Recessive:

a disorder caused by a recessive gene located on an autosome.

Define X-Linked:

a disorder caused by a gene located on the X chromosome.

Define Microcephaly:

a condition in which the head is smaller than normal.

Define Macroorchidism:

Large Testicles

What is the Human Genome Project and what is it’s significance?

A research study from 1990–2003 that mapped the human genome

Significance: It helped link thousands of diseases to specific genes and opened the door for pharmacogenomics.

What is DNA’s role in genetics and disease?

DNA contains genes that carry directions for proteins and enzymes. Un-repaired DNA damage can result in disease.

What is Gene’s role in genetics and disease?

Gene’s role in genetics and disease: Genes carry directions for proteins and enzymes. Mutations in genes can cause disease.

What are chromosomes role in genetics and disease?

Chromosomes store the genetic information created by DNA and RNA and contain multiple genes. Chromosomal disorders can result when chromosomes do not split correctly during meiosis, often causing an abnormal number of chromosomes.

What are RNA’s role in genetics and disease?

RNA arises from transcribed DNA and carries the directions and needed amino acids to build proteins.

Explain Recombinant DNA technology.

DNA is split, altered, and inserted into a one-cell organism, where the DNA replicates. The DNA is then extracted.

What is the difference in congenital and genetic?

Congenital: Present at birth.
Genetic: Due to a genetic mutation.

What is penetrance and expressivity with relation to genetics?

Penetrance: The likelihood that your phenotype will reflect your genotype.

Expressivity: How pronounced the phenotype will be.

Describe X-linked inheritance patterns.

Disorders caused by a gene on the X chromosome. They usually affect males. Fathers pass the defective gene to all daughters and none of their sons. Mothers have a 1 in 2 chance of producing an affected male or a carrier female. Females are rarely affected because they would need 2 affected X chromosomes.

What is meant by multifactorial inheritance and give examples of diseases of multifactorial inheritance patterns.

Multifactorial inheritance: Inheriting a predisposition to develop a disorder, with environmental triggers contributing to disease development. There is no direct gene linkage.

Examples: Coronary artery disease, diabetes mellitus, hypertension, manic depression, schizophrenia, cleft lip/cleft palate.

What is the pathophysiology or chromosomal disoders?

They result during meiosis when a chromosome does not split correctly, most frequently causing an abnormal number of chromosomes.

What are the prenatal diagnostics tools available and when are each indicated?

Prenatal diagnostic tools:

• Ultrasonography: Visual exam of structure and function.

• Alpha-fetoprotein: Maternal blood test to detect an open neural tube or open ventral wall.

• Amniocentesis: Amniotic fluid sample to detect chromosomal defects.

• Chorionic villus sampling: Placental biopsy to detect genetic defects.

• Percutaneous umbilical blood sampling: Collection of cord blood to determine genetic defects.