Chapter 6 Vocabulary Flashcards
Mechanism by which genes are passed on from parents to offspring
Transmission Genetics
Each individual has two copies at every locus in the genome. Disproved blended inheritance
Mendel’s Law: Segregation
Genes at one locus are independent of other loci (do not blend)
Mendel’s Law: Independent Assortment
Basic unit of heredity
Genes
Variation of the same sequence of nucleotides at the same place on a long DNA molecule
Alleles
Expressed in heterozygote
Dominant
Not expressed in the heterozygote
recessive
Offspring is a combination of both parents
particulate inheritence
Offspring is a blend of parents
Blended inheritence
Instructions contained in a gene that tell a cell how to make a specific protein
genetic code
Multiple codons encoding fro one amino acid
redundancy
differences in the frequency of occurrence of synonymous codons in coding DNA. (some used more than others)
codon bias
Heritable mechanisms that alter gene expression without changes to DNA (phenotype change without genotype change)
Epigenetic inheritance
What are the four ways epigenetic inheritance happens?
cell differentiation
genomic imprinting
X inactivation
developmental plasticity (prenatal)
often stops transcription by blocking promoters and RNA polymerase
Methylation
Influences transcription through decondensation
histone modification
functional RNA molecule that is not translated into a protein and serves many roles
NC RNA
What are the four sources of variation?
recombination, mutation, migration, lateral genes transfer
DNA is broken down and recombined to produce a new combination of alleles
Recombination
Creates new versions of genes through many different mechanisms
mutation
Movement of individuals or gametes from one population to another (gene flow)
migration
Transmission of genes other than the transmission of DNA from parent to offspring (1+2 within population, 3+4 outside population)
Lateral gene transfer
ultimate source of variation
mutations
Point mutation that results in a premature stop codon
Nonsense
Substitution of one base for another, does not change encoded amino acid sequence (silent mutations)
Synonymous mutation
Substitution alters the AA sequence
Non-synonymous mutation
One or more nucleotide base pairs added into DNA sequence
Insertion
Loss of one or more nucleotides from a segment in DNA
Deletion
Insertion or deletion changes the reading frame, resulting in a completely different translation from original
Frameshift
copy of gene or region of genome
gene duplications
segment of chromosome is duplicated
chromosomal duplications
pieces of chromosomes are missing, duplicated, or moved around
Chromosomal rearrangements
segment of chromosome is turned 180 degrees
inversion
Segment of chromosome moves from one chromosome to a nonhomologous chromosome or another place on the same chromosome
translocation
whole sets of chromosome changes
ploidy
Two hypotheses for mutations
- Random mutation (correct)
- ACquired hereditary resistance (incorrect)