Topic 5 Flashcards
Reservoir of genetic information is
the individual
DNA stands for
deoxyribonucleic acid
DNA composed of
4 different nucleotides arranges in alpha helix (A, C, T, G)
DNA is contained on
threadlike structures called chromosomes
Chromosomes come in
matched pairs. one from each parent
DNA is organized into
discrete subunits called genes (code for a protein)
Tay saches disease
individual doesn’t produce an enzyme (protein) called hexosaminidase A without which fatty tissue develops around nerve cells
Locus
particular location of a gene on a chromosome
Alleles
two or more alternative forms of a gene
Heterozygote
individual that has different alleles at a locus on the pair of chromosomes (Aa)
Homozygote
individual that has same alleles at locus on the pair of chromosomes
Genotype
all genetic characteristics of an individual. encoded in DNA. FIXED for the lifetime. (set of genetic instructions)
Phenotype
interaction of the genotype of an individual with its environment. physiology, appearance or behaviour expression. (not fixed may change)
Mendelian inheritance
breeding of two individuals results in multiple combinations of alleles. how genetic variation is maintained
1 allele is present on
each chromosome of a parent
1 chromosome is present in
each gamete produced by a parent
Gametes
combine in offspring to form new combination of alleles
Genetic recombination
all possible allele combinations from random mating of any combination of individuals in a population
Medelian inheritance
how genetic variation is maintained
Phenotypic expression can be/often is..
continuous
More than one set of genes is responsible for..
a particular trait
Gene expression can also be affected by ..
the environment
Phenotypic plasticity
ability of a genotype to alter its phenotypic expression under different environmental conditions
Phenotypic variation can be expressed as ..
- discrete
- continuous
Discrete phenotypic variation
alternative forms, ex:insects like bees and ants. the two types of larvae hatch with essentially the same genetic material but different duties (queens or workers)
Continuous phenotypic variation
continuous variations form
Reaction norm
relationship between response of a continuously varying trait and environmental conditions
1 genotype can result in..
many phenotypes
Daphnie
respond pigmentation to varying UV radiation so level of pigment varies continuously to response to UV and predator (continuous variation)
The individual
reservoir of genetic information, unit of evolution
The population
group of individuals of the same species living together, where the effects of evolution are observed
Species rarely consist of..
single continuous interbreeding population
Metapopulation
groups of sub populations consisting of interbreeding individuals. linked by the movements between subpopulations
Gene pool
sum of genetic information of all individuals within a population
Hardy Weinberg Principle
genetic composition (allele frequencies) within a population does not change (evolutions doesn’t occur) unless one of his assumptions are broken
Hardy Weinberg Principle assumptions
- no mutations
- no migrations
- large population size
- random mating
- no selection
