Genetic variation Flashcards
Explain what it means when genetic variation can be visible or invisible
- Visible: changes in coding region = changes in phenotype
- Invisible: changes in non-coding region or in regulatory sequences (silencer, promoter) ≠ change in pheno.
How does variation change between related individuals? Related species? Unrelated species?
Related individuals: less variation
Related species: less
Unrelate species: more
What does genetic variation lead to?
Evolution: provide survival advantage and/or genetic disease
What is the difference between continuous variation and discontinuous variation?
- Continous: phenotype controlled by multiple genes
- Discontinuous: phenot. controlled by 1 or few genes
What are some of the applications of genetic variation?
- Forensics: paternity testing, identification
- Evolutionary relationships: look @ conserved reg. in species
- Health: diagnose & find treatment
- Production: selective breeding (make more for less)
- Biotechnology: detect how gene works
Difference between natural and induced sources of genetic variation
- Induced: Selective breeding e.g. wolves domesticated => dogs; (experiments?)
- Natural: Natural selection; Errors in DNA replication; Natural selection; Sexual Repro.
List & describe the mechanisms of population variation
- Mutation: Carriers for (brown) gene => brown offspring = more brown gene
- Migration: Frequency of brown gene diff.
- Genetic drift: changes in population due to chance
- Natural selection: the trait w/ a survival adv. more likely to survive = repro. more
Explain what it means when “populations can have multiple alleles at a single locus.”
This refers to a certain gene (e.g. eye colour) found @ a locus. Individuals in a population will only have 2 alleles for a colour (diploid). But when you combine the alleles from all indiv. in a population you get multiple copies
What changes (mutations) can occur @ a chromosomal level = chromosomal variance? (2types)
Change in:
- Structure: Deletion, Duplication, Inversion, Recombination (relocate gene on diff loci)
- Number: Monoploid, Polyploid, Autotetraploidy, Extra or missing chromo. (Non-disjunction)
Define Monoploid, Polyploid and Autotetraploidy
- Monoploid: one copy/allele @ each chromo.
- Polyploid: multiple copies/alleles
- Autotetraploidy (plants): 4 copies/alleles = more gene info. = larger plants
Differentiate between the 3 changes (mutations) that can occur @ a DNA level: point mutations, small segment, chromosomal
- Point mutation: change in single nucleotide
- Small segment: change parts in gene
- Chromosomal: change parts in chromo.
What’s the difference b/w Gene mutation & chromosomal mutation?
- Gene: change in 1 base = 1 gene affected
- Chromo.: a number of genes are affected
Give an example of a disorder that involves an extra chromo. and another with a missing chromo.
- Extra: Klinfelter’s (XXY), Patau syndrome (extra in chromo. 13)
- Missing: Turner’s syndrome
What can the Hardy Weinberg Principle be used for?
used to determine current allele freq. in population & predict future allele freq.
=> predict whether variation will occur or likely die
a) Regions which may be affected by point-mutation.
b) Outcomes
a) non+coding, regulatory, intergenic regions
b) - incorrect protein
- No protein
- Incorrect splicing
- Incorrect sorting &/ stability of RNA
