An organism’s physical traits
Phenotype
How does DNA determine our physical traits?
DNA holds instructions for how to build proteins
Different variants of the same gene
Allele
MC1R Gene
- codes for a protein that directs pigment in hair and skin
- 80 variants of MC1R gene within the human population
Protein Synthesis Basic Steps
- Transcription –> translation
- DNA –> mRNA –> Protein
Transcription
RNA copy of a gene is made
Translation
RNA is used as a template to build the protein
DNA and RNA made up of a sequence of
nucleotides
Proteins made up of a sequence of
amino acids
How does DNA sequence influence phenotype within an organism
- genetic information flows from DNA to RNA to proteins
- proteins perform most of the functions in cells, so they determine our traits
- differences in proteins can give organisms different traits
- DNA dictates the production of proteins
- specific arrangement of nucleotides in gene determines amino acid sequence of protein it encodes, this protein sequence directly impacts organism’s characteristics and functions, shaping its phenotype
Genetically Modified Organism
changes in its DNA were introduced intentionally to generate a new trait
Method by which GMOs are created
genetic engineering
Transgenic organism
- have a gene from another species
- most have just one added gene from another organism
- ex. glofish
- Genetic engineering - purpose
- produce medicines - insulin (in large quantities), vaccines
- food - more nutritious, healthier, less expensive
- treat disease - cancer, genetic diseases
- research - to figure out the function of genes
Bt Corn
- most abundant GMO on the market
- in 2020 80% of corn is Bt
- contains a pesticide toxin from the bacteria, Bacillus thuringiensis
- produces protein that protect against insect pests
AquAdvantage Salmon
- first GM animals on the market
- growth gene from pacific salmon added to Atlantic salmon
- allow transgenic salmon to grow year round and reach market size much earlier
GloFish
has a gene from jellyfish called “green fluorescent protein” or GFP that produces a fluorescent color
Benefit of genetically modified crops and food
more nutritious, healthier, less expensive
Potential risks of GMO food
- health risks
- environmental risks: Bt corn harmful to good insects? AquAdvantage fish escape and become an invasive species?
GMOS pros
- no scientific evidence has been found that GMOs pose any risks to humans or the environment
- voluntary and mandatory safety measures are in place, with a ban on certain dangerous lines of research
- GMOs can be more nutritious than standard crops and can be grown in a wider variety of habitats
- strains of microorganisms used in recombinant DNA experiments are genetically crippled so they cannot survive in the wild
GMOs Cons
- may be hazardous to human health/environment in ways that we cannot yet understand
- might escape into the environment and cause unforseen problems by passing genes to wild organisms
- widespread use of GMOs may promote loss of biodiversity
- no standard for labeling GMOs in the U.S, consumers don’t know what they are getting
Selective Breeding vs. GMOs
- a lot of GMOs are transgenic- genes from different species
- selective breeding- breeding for different traits and different gene variations, but all the DNA is still of that species
- GMOs can be produced faster, in the lab while selective breeding takes generations
- number of genes- selective breeding- enrich for good and bad genes (dog breeds that are prone to certain diseases
- cost of development (GMOs more upfront costs/technologies)
*transgenic technology: achieve wider variety of desired traits in organisms faster
