Understanding Genetics: DNA, Genes, and Engineering
Stem Cells
Stem cells retain the ability to renew themselves through self-division. They can differentiate into a range of specialized pluripotent cells, retaining the ability to change into other cells.
Inherited vs. Acquired Characteristics
Inherited variations are received from genes from your parents. Acquired variations are not present at birth; you learn or acquire them throughout your life.
DNA Structure
Deoxyribonucleic acid (DNA) is hereditary material that carries and passes on genetic information. The DNA double helix consists of two parallel strands, each with a series of bases on the inside. The bases are directly opposite each other and link in pairs, forming the steps of the ladder. The bases are: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). The base pair rule is: A-T, C-G.
Non-coding DNA: 97% of DNA is non-coding. Coding DNA contains information to make proteins. Scientists: Dr. James Watson and Francis Crick.
Gene
A gene is a length of DNA that codes for a specific protein. It is the unit of inheritance and is found on a chromosome. It contains instructions to make a particular protein. Chromosome structure: 60% protein, 40% DNA.
DNA Profiling
All human chromosomes have sections of DNA with no known functions. These sections have short base sequences that repeat. They are inherited from parents, and their length and position are unique to each person. DNA profiling is a process or technique of analysis revealing unique patterns of an individual’s DNA involving non-coding regions. Applications of genetic screening include paternity disputes, forensic science, and genetic screening.
Genetic Engineering
Genetic engineering is the addition, deletion, or manipulation of a single trait in an organism to create a desired change. It allows genes from one organism to be inserted into a cell of a different organism or species. Organisms are altered by genetic engineering, and genetic material is changed by means other than random natural breeding. Gene transfer involves moving a gene from one organism to another. GMO stands for genetically modified organism, and GEO stands for genetically enhanced organism. Examples include plants that resist a particular type of weed killer and sheep that produce a special substance in their milk. The five stages involved in genetic engineering are isolation, cutting, ligation and insertion, transformation, and expression.
Species and Crosses
A species is a group of organisms capable of interbreeding and producing fertile offspring. Examples of crosses include:
- Liger: male lion, female tiger
- Tigon: male tiger, female lion
- Hinny: male donkey, female horse
- Cabbit: male cat, female rabbit
- Geep: male goat, female sheep
- Zorse: male zebra, female horse
Genetic Screening
Genetic screening is the use of simple diagnostic tests performed on a large number of individuals to identify those at high risk of having or passing on a specific genetic disorder.