Plant Domestication and Biotechnology

Plant Domestication

A process by which plants or animals are selected and genetically modified over time for traits that make them more advantageous or desirable for human use, contributing to the development of agriculture and civilization.

Common Traits Changed During Plant Domestication

Include large fruit/seed size, loss of seed dormancy and shattering, improved plant architecture for harvesting, uniform maturation, reduction in bitter/undesirable flavors, and loss of seeds.

Modern Corn

Derived from teosinte through domestication, featuring large grains, no covering, and permanent attachment of seeds to the cob encased by a tough husk.

Heterosis (Hybrid Vigor)

The tendency of a crossbred individual to show qualities superior to those of both parents; can also be defined as the tendency of a hybrid individual to exhibit phenotypes that exceed the average of the parents.

Sources of Genetic Variability (Sexual Reproduction)

Include crossing over during meiosis I, independent assortment of homologous chromosomes, and random fertilization of gametes, leading to genetically unique offspring.

Sources of Genetic Variability (Conventional Breeding)

Include wild relatives, natural and induced mutations, and artificial hybrid crosses (e.g., Triticale from Wheat X Rye).

F1 Hybrid Strawberries (Day Neutral)

Strawberry varieties that can be grown from seed, flower and produce fruit throughout the year, offering advantages like reduced risk of infection from pests and diseases and higher yield. 

Inbreeding Depression

A loss of vigor in homozygous individuals, often caused by the expression of deleterious traits determined by recessive alleles.

Biotechnology (Genetic Variability)

The transfer of genes from one organism to another to create a 'transgenic organism' (GMO), facilitated by tools like Agrobacterium, direct DNA uptake by protoplasts, and gene editing (CRISPR).

Transgenic Organism (GMO)

An organism created by transferring genes from one organism to another, often by introducing foreign DNA.

Agrobacterium-mediated Plant Transformation

A natural gene transfer system where Agrobacterium tumefaciens, a soil bacterium, introduces a portion of its Ti (tumour-inducing) plasmid, called T-DNA, into a plant's genome at a wound site. Normally, this causes Crown Gall Disease. But scientists can manipulate the t-dna to induce other desired traits.

GM Crops (Production Focused Traits)

Traits developed through genetic modification to make farming easier, reduce inputs (pesticides), and increase yields, such as herbicide resistance (Roundup-ready plants), insect resistance (Bt toxin), and viral resistance.

GM Crops (Food Focused Traits)

Traits developed through genetic modification to improve food quality, such as extended shelf life (e.g., FLAVR SAVER Tomato, Arctic Apple with reduced polyphenol oxidase) and enhanced nutritional value.

Gene Editing (CRISPR-Cas9)

A new technology for making precise changes in DNA without leaving foreign DNA behind, using specific guide RNA sequences to target the Cas9 protein to a precise genome locus where it cuts the DNA, allowing cellular repair machinery to introduce insertions, deletions, knockouts, or modifications.