Lecture 5: Phenotype, Genotype, and Variation Flashcards
Define phenotype
The physical appearance or attributes of an organism
Define genotype
genetic make up of an individual
Define dominance
one allele determines the phenotype of the diploid genotype
Define recessive
one allele is ‘masked’ in its expression pf phenotype (by dominant allele)
Define co-dominant
the heterozygote is intermediate between the two homozygotes
What is Wiesman’s doctrine
sequestration of the germ line
What are the types of mutations?
- Point mutations
- Deletions
- Duplications
- Inversions
- Translocations
- Transposable (mobile) elemnts
What are the four types of point mutations? And what type of change it it?
- Synonymous (no amino acid change)
- Nonsynonymous (changes amino acid)
- Transitions (purine-purine or pyr-pyr)
- Transversion (purine-pyrimidine
What is the significant of mutations?
They can create new genes by inverting different portions or removing a stop codon, etc . This then causes variation among different populations.
Define phenotype plasticity
The ability of one genotype to produce more than one phenotype when exposed to different environments.
What are the different ways to measure variation?
- Resemblance among relative
- Discrete polymorphisms
- Frequencies of types in the population
What are the components of the “classical” school of variation?
- Low levels of genetic variation in natural populations
- “Wild type” is favored, mutants are eliminated
- “Purifying” selection
What are the components of the “balance” school of variation?
- Genetic variation is common in natural populations
- Maintained by balancing selection
- Heterozygotes are favored, maintaining both alleles
Know how to calculate allele frequencies and genotype frequencies.
Allele freqeuncies - # of specific allele/over all alleles
What are VNTRs?
Variable number of tandem repeats, a location on the genome where a short nucleotide sequence is organized as a tandem repeat
