Inheritance Flashcards
Phenotype
An observable or measurable feature of an organism
- anatomical
- biochemical
- behavioral
* can be almost anything
Genotype
The genetic makeup of an individual
- overall
- variants at a specific locus
Can an organism carry genetic information that is not observable?
YES; genotype is not always expressed in the phenotype!
Mendels experimental design
Peas
- self-fertilization
- created true-breeding strains (he was sure that phenotype corresponded directed to the genotype)
- he recorded the pedigree (parent and offspring relationships through many generations)
- the pea traits have two types (yellow and green)
- he had a large sample
- he repeated his experiment
Mendel’s Postulate 1: Hereditary characteristics are controlled by particulate unit factors that exist in pairs in individual organisms
There are units of inheritance in the form of particles (chromosomes)
- they are paired (one from each parent)
* these units of inheritance can have different versions
Alleles
Different versions of genetic information
Locus
The location of genetic information
Homozygous
Both copies of genetic information have the same allele
Heterozygous
Each copy of genetic information has a different allele
Mendels Law 2: Dominance- when an individual has two different unit factors responsible for a characteristic, only one is expressed; that unit factor is dominant over the other, which is recessive
One allele can cover up the expression of the other
Dominant
Allele that we can observe in the phenotype
Recessive
An allele that is in the genotype but not observable in the phenotype
Polygenic
Descriptor for a phenotypic trait that is influenced by more than one gene
Pleiotropic
Descriptor for a gene that affects more than one phenotypic trait
Sexual reproduction combines…
genetic information from two haploid gametes