CHAPTER 3.1 Mechanisms and Processes of Evolution Flashcards
- descent with modification from a common ancestor
- change in gene frequency within a population
evolution
Mechanisms of Evolutionary Change
MMGNM
Mutation
Migration/ Gene Flow
Genetic Drift
Natural Selection
Modern Evolutionary Synthesis
Mechanisms of Evolutionary Change
- changes in the DNA
- happens in the central dogma
mutation
what happens in central dogma?
In interphase, the DNA is duplicated, replicated and transcripted.
The DNA template separates, copies DNA template forming replicated DNA. The replicated DNA is attached to mRNA. The mRNA will then transcribe the DNA into RNA template. After transcribing, the RNA will move out of the nucleus, the mRNA strans will attach with rRNA. There are small rRNA under the RNA and the bigger rRNA at the top, the rRNA atop will be attach to tRNA. The tRNA translates mRNA template into protein or polypeptides.
- hereditary material of life that carries genetic information from generation to generation
- backbone -
- 3 bonds Adenine and Thymine
- 2 bonds Cytosine and Guanine
- due to polarity, the shape “helix” forms
deoxyribonucleic acid DNA
sugar phosphate
Mechanisms of Evolutionary Change: MUTATION
- the most that instigate evolution
- are inherited genetic alterations that occur in germ cells (sperm, eggs)
germline mutation
Mechanisms of Evolutionary Change: MUTATION
- involves cells that do not participate in meiosis
- genetic alterations acquired by a cell that can be passed to the daughter cells of the mutated cell in the course of cell division
Why does this type of mutation not instigate evolution?
—
somatic mutation
Because they do not pass on to generations and are not acquired by offspring.
Types of Mutation
Gene mutation
Chromosome mutation
Genome mutation
Gene Mutation Types
Point Mutation
Frameshift Mutation
Types of Mutation: Gene Mutation
- substitution of a single base in the third nucleotide position of codon
point mutation
Types of Mutation: Gene Mutation: Point Mutation
- has no effect on the protein sequence
silent
Types of Mutation: Gene Mutation: Point Mutation
- results in an amino acid substitution
- 1st and 2nd base nucleotide position in codon that causes change in proteins
missense
Types of Mutation: Gene Mutation: Point Mutation
- substitutes a stop codon for an amino acid
nonsense
Types of Mutation: Gene Mutation:
- insertion/ deletion of one or more bases
- causes shift in reading frame
frameshift mutation
Types of Mutation: Gene Mutation: Frameshift Mutation
- shortened/ lengthened - nonfunctional protein sequence
insertion/ deletion
Types of Mutation: Chromosome Mutation:
change in the amount of genetic information in chromosome because of:
—- loss of chromosomal segment, ex. Cri du Chat
—- gain/ repetition of chromosomal segment, ex. Charcot-Marie-tooth Disease
deletion
duplication
Types of Mutation: Chromosome Mutation:
a similar amount of genetic information but the materials are rearranged
— reversal of region
— a segment of one chromatid attached to another chromatids segment
inversion
translocation
Types of Mutation: Genome Mutation:
________ - presence of abnormal number of chromosomes; common on humans
________ - presence of more than two homologous chromosome sets; natural miscarriage
autoploidy
allopolyploidy
aneuploidy
polyploidy
a. mutations are random - beneficial, neutral, harmful
b. not all mutations matter to evolution - ex. —
- single mutation has a large effect on the evolution
- but evolution happens in an —-
somatic mutations
accumulation of many mutations
Causes of mutation
- DNA fails to copy accurately
- exposure to specific chemicals or radiation (external influences)
Mechanisms of Evolutionary Change:
any movement of genetic materials/ individuals in a population to another population
gene flow
Mechanisms of Evolutionary Change: GENE FLOW: Types of Gene Flow
- two population of the same species
- mediated by reproduction
- increases genetic variation of the population
- ex. grafting (Solanum lycopersicum and Solanum melongena)
vertical gene transfer
Mechanisms of Evolutionary Change: GENE FLOW: Types of Gene Flow
- two different species
- known as lateral gene transfer
- bacteria/ viruses, endosymbionts to the host
- decreases genetic difference between different species
horizontal gene transfer
Mechanisms of Evolutionary Change: GENE FLOW
Restrictions of Gene Flow
- physical barriers
- incompatible reproductive behaviors
Mechanisms of Evolutionary Change:
- allele frequencies of a population change over generations due to chance or sampling error
ultimately separated
- random chance in allele frequencies independent to the influence of alleles’ to reproduce successully
- occurs in all populations of non-infinite size, but its effects are strongest in small populations (endagered species)
GENETIC DRIFT
Mechanisms of Evolutionary Change: GENETIC DRIFT: Types of Genetic Drift
- sharply reduced in size by natural disaster; survival of cheetah -
- small group splits off from the main population to found a colony; Amish History, i.e. Ellis-van Creveld Syndrome (six-fingered dwarfism)
if genes are not varied, if pandemic happened, they could be wipeout
- bottleneck effect
- founder effect
