Genetics
Genetics is the scientific study of heredity and hereditary variation. Molecules such as DNA and RNA are used to store genetic material within living things. In a cell, transcription and translation allow the inherited information to flow from DNA to RNA to protein.
DNA Transcription (to mRNA) and mRNA translation (to proteins)
2. Elongation- The polymerase begins moving down, unwinding the DNA and lengthening the RNA transcript. Eventually, the DNA strands re-form a double helix.
3. Termination- The RNA transcript is released, and the polymerase disconnects from the DNA.
DNA Transcription (to mRNA) and mRNA translation (to proteins)
- DNA transcription is a process that transcribes genetic information from DNA to RNA. A DNA strand can serve as a template for creating a complementary sequence of RNA nucleotides. The resulting RNA molecule is a transcript of the gene’s protein building instructions. mRNA is a type of RNA molecule that carries genetic messages from the DNA to the protein synthesizing machinery of the cell.
- There are three main steps included in the process of DNA transcription.
2. Elongation- The polymerase begins moving down, unwinding the DNA and lengthening the RNA transcript. Eventually, the DNA strands re-form a double helix.
3. Termination- The RNA transcript is released, and the polymerase disconnects from the DNA.
- Translation is the synthesis of a polypeptide, which is directed by mRNA. During this process, the cell translates the base sequence of an mRNA molecule into the amino acid sequence of a polypeptide. The sites of translation, ribosomes, enable the linking of amino acids into polypeptide chains.
- The genetic message that directs the creation of a polypeptide chain during translation is interpreted by transfer RNA (tRNA). tRNA transfers amino acids to a ribosome. The ribosome adds each amino acid to the growing end of a polypeptide chain.
Probability of Gene Inheritance
- The punnett square is a technique invented by an English geneticist named Reginald Punnett that is used to calculate the mathematical probability of inheriting a specific trait. It is a graphical way of discovering all of the possible combinations of genotypes that can occur in children, based on the genotypes of their parents. It also shows the probability of the offspring genotypes occurring.
- The probability for any genotype among the offspring of two heterozygotes can be determined by multiplying together the individual probabilities of an egg and sperm having a specific allele.
- To determine an organism’s genotype, geneticists can also perform a testcross. In this type of technique, the individual with the unknown genotype is crossed with a homozygous individual expressing the recessive trait, and Punnett squares are used to determine the possible outcomes.
Effects of Mutations in Genome
- Mutations result either from errors in DNA replication or from the damaging effects of mutagens, such as chemicals and radiation. A mutation in a gene can cause the cell to die if the protein coded by the mutant gene is not working.
- Some mutations are natural errors in replication that avoid the proofreading function of the DNA polymerases that synthesize new polynucleotides at the replication fork. These mutations are positions where the nucleotide that is inserted into the daughter polynucleotide does not match.
- A point mutation is when a single base pair is altered. Point mutations can have tremendous effects in genome. For example, the base substitution can be a missense mutation where the altered codon matches with a different amino acid.
Forms of Biotechnology and its Uses in Modern-Day Genetic Research
- Gene Cloning is the production of multiple copies of a single gene and is commonly used in modern day genetic research. It is useful in making many copies of a particular gene and in producing a protein product.
- Gel electrophoresis is a technique used to study DNA molecules. It is used for separating nucleic acids or proteins that differ in size, electrical charge, or other physical properties. Restriction fragment analysis can rapidly provide useful information about DNA sequences based on this technique.
- DNA microarray assays helps scientists study genome-wide expressions. It consists of tiny amounts of a large number of single-stranded DNA fragments representing different genes fixed to a glass slide in a tightly spaced array. These arrays reveal general profiles of gene expression over the lifetime of an organism. DNA microarray assays also contribute to a better understanding of diseases and propose new diagnostic techniques or therapies.
Sources-
YouTube-Dihybrid Punnett Square- https://m.youtube.com/watch?y=qRxylc4vMga
Pearson- Ap* Edition Biology- pgs. 328-348, 396, 410, 470
National Center for Biotechnology Information- Mutation, Repair, and Recombination- http://www.ncbi.nih.gov/books/NBK21114/
Memorial University of Newfoundland - Principles of Cell Biology - http://www.mun.ca/biology/Penn State University - Using a Testcross - https://online.science.psu.edu/biol011_active002/node/4226
Wikipedia - Point Mutations - http://en.wikipedia.org/wiki/Point_mutationHouston Community College - Biotechnology - http://learning.hccs.edu/faculty/e.miliamcamacho/biol1406/biol-1406-general-biology-i/chapter-20-biotechnology
Stanford- Huntington's Outreach Project for Education, at Stanford- http://web.stanford.edu/group/hopes/cgi-bin/wordpress/2011/03/genetic-testing/
YouTube-Dihybrid Punnett Square- https://m.youtube.com/watch?y=qRxylc4vMga
Pearson- Ap* Edition Biology- pgs. 328-348, 396, 410, 470
National Center for Biotechnology Information- Mutation, Repair, and Recombination- http://www.ncbi.nih.gov/books/NBK21114/
Memorial University of Newfoundland - Principles of Cell Biology - http://www.mun.ca/biology/Penn State University - Using a Testcross - https://online.science.psu.edu/biol011_active002/node/4226
Wikipedia - Point Mutations - http://en.wikipedia.org/wiki/Point_mutationHouston Community College - Biotechnology - http://learning.hccs.edu/faculty/e.miliamcamacho/biol1406/biol-1406-general-biology-i/chapter-20-biotechnology
Stanford- Huntington's Outreach Project for Education, at Stanford- http://web.stanford.edu/group/hopes/cgi-bin/wordpress/2011/03/genetic-testing/