Genetics Flashcards
Genes
DNA units in chromosomes coding for a particular protein or characteristic
Allele
- A form of a particular gene
- Alleles occupy the same locus of a particular chromosome
- One gene/allele is inherited from each parent
Artificially crossed
Breeding controlled by humans, usually to create organisms with specific traits.
Dominant allele
An allele which is expressed over a recessive allele
Recessive allele
An allele not expressed in the presence of a dominant allele
Genotype
The genetic makeup of a particular organism
Phenotype
- The observable traits,
- determined by both genotype and the organisms environment
Locus
Specific place or position (on a chromosome)
Offspring
Children or young of particular parent(s)
Selective breeding
Intentional mating of two organisms to promote specific trait(s)
Self pollinate
Transfer of pollen from anther to stigma of same flower or plant
Pure/true-breeding
Self fertilized or two pure-breeding organisms consistently produce offspring with the same particular trait
Trait
- In genetics, a characteristic of an organism.
- Some are visible e.g. Eye colour
- Some not easily seen e.g. Blood type
Who was Gregor Mendel
- Austrian monk in mid 1800’s
- Quantitatively showed that parent plants pass on factors of inheritance (genes)
- some factors not expressed but still able to be passed on
Mendel’s focus group and what he did with them
- Pea plants
- Thousands of selective breeding events e.g. forcing self and cross-pollination examining particular traits
- Starting with true-breeding plants for a particular trait he crossed them with other true-breeding plants
- Recorded traits of offspring
Why pea plants for Mendel’s experiments?
- grow and reproduce quickly
- many traits in one species
- easy to control reproduction (naturally self-fertilizing but can be cross-fertilsed)
- True-breeding strains for particular traits already available to him
Seven traits Mendel studied in peas
- Seed shape
- seed colour
- flower colour
- pod shape
- pod colour
- flower position
- plant length
Mendel’s three laws
- Segregation
- Dominance
- Independent assortment