Genetic variation Flashcards
what is a gene pool
all the genes in a population
what is a population
a group of individuals from the same species that interbreed
what is drift
changes frequency via random sampling
what are traits
variants of phenotypic character(s) of an organism that may be inherited, determined by the environment, or by both and are visible
what is a polymorphic loci
any locus that has more than one allele present within a population
what is QTLs
Quantitative Trait Loci
what is heterosis
hybrid vigour
what is genetics
study of heredity
how are genes passed on
gene passes from one generation to the next, dictates the inherent properties of a species
what are genes
functional units of chromosomes
what is the discipline of genetics
- transmission genetics e.g. peppered moths - due to change in environment
- molecular genetics
- population genetics
- quantitative genetics e.g. height in humans, many genes affect this
what is genetic variation
variations of genomes between members of species, or between group of species thriving in different parts of world – result of genetic mutation
what is genetic diversity
diversity in a population or species is a result of a new gene combinations, genetic mutations, genetic drift etc.
what is the importance of genetic variation
- maintain biodiversity among species
- selection of strongest individuals to guarantee species survival, leading to evolution
- pool of genes pass to next generations
why is genetic variation important to study
- in any form of breeding, natural or artificial, variation must be present for desired characteristics
- whatever the breeding system the selection of the “parents” is very important – they must show the required variation
what are the two main sources of genetic variation
natural
induced
what are the natural sources of variation
intra-specific
inter-specific
what are the induced sources of variation
- polyploidy
- mutagens
- genetic engineering
what is divergence of populations
Patterning of genetic variation in and between populations is dynamic process
Loss/fixation of variations via drift and creation of new genetic variation via mutation (and perhaps migration) is a constant background process
Populations can also evolve via natural selection to be locally-adaptive
what causes genetic divergence
- drift and mutation cause allele frequencies to change between populations
- breeder usually interested in those genetic changes made by natural selection and exploits genetic adaptation and genes that underlay these adaptive traits
what is intra-specific variation
range of genetic information available among all individuals of a species
survival of fittest ensures gene pools of natural variation exist in natural populations e.g. different in natural populations, i.e. different genes in different environments
what is inter-specific genetic variation
range of genetic information available of related species that don’t normally sexually reproduce together
what is inter generic genetic variation
range of genetic information available of different GENERA that don’t normally sexually reproduce together (e.g. sheep and goats)
what is inter familal genetic variation
range of genetic information available of different FAMILIES that don’t normally sexually reproduce together, extremely rare (e,g, guineafowl hybrids)
what is polyploidy
increase of complete sets of chromosomes; usually induced with chemicals (colchicine)
what is genetic engineering
manipulation of DNA of organisms, change inheritance or in vitro manufacture of gene products. Introduction of new DNA doesn’t use classical genetic methods, traditional breeding methods are typically used for the propagation of recombinant organisms
how is genetic variation measured
- phenotype:
> proportion of polymorphic loci
> Heterozygosity (H) - protein electrophoresis
how is genetic variation quantified
statistics (ANOVA)
how is genetic variation measured
at protein level
protein electrophoresis
could quickly determine genotypes of many individuals at many loci
what is protein electrophoresis
proteins separated as they move through a gel matrix according to charges of amino acids
problem with protein electrophoresis
may miss much of the variations due to silent or synonymous variations
what are synonymous changes
change at site that don’t change amino acid sequence of resulting protein
what are non-synonymous changes
changes occur at nucleotides that change the amino acid sequences of resulting protein
why are there large amounts of nucleotide diversity at synonymous sites
because the changes do not affect the function of a protein
how is genetic variation at DNA level measured
DNA sequence variations can be detected by
1) gel electrophoresis
2) restriction enzymes
what are the patterns on gels called
restriction fragment length polymorphisms (RFLPs)
what information does the patterns on gels provide
RFLPs can be used to provide information about how DNA sequences differ among individuals
