module 6 gen 8-10 Flashcards
Why are recombination events considered rare?
Recombination events occur less frequently than mutations, especially within specific regions of DNA.
What is meant by “wild type”?
Wild type refers to the normal or most common phenotype or genotype found in a population.
What is the potential outcome of recombination between two independent mutations in the same gene?
The outcome could be the restoration of functional protein, leading to the wild-type phenotype
What is the significance of rare recombination events within a gene?
Rare recombination can restore the original wild-type sequence by swapping mutated segments with wild-type segments.
How is a gene defined in the context of mutations?
A gene is a linear arrangement of nucleotides that encodes for a specific protein or function.
What happens when two independent mutations occur in the same gene?
They may affect the gene’s function but can potentially be restored to wild-type through recombination.
seymor benzer did a
recombination analysis
seymor benzer proposed
if a gene is a inear set of nucleotides then recombination between
homologous chromosomes carrying different mutations within the
same gene should generate wild-type phage(
Benzer studied a mutation that
leads to
very rapid lysis of
bacteria
seymor benzer used ____ as an experimental system
T4 phage
T4 is _____ , but several different strains can infect E. coli
_______
haploid; simultaneously
Different viral genomes can ______
recombine
There is a large number of progeny to detect rare
recombination events (screening)
Only recombinant phages could
proliferate
Lytic Phage Life Cycle
1.phage injects dna into host cell
2.phage proteins made.dna replicated. host chromosome degrades
3.assembly of phages in host cell
4.lysis of host cell
the mutation seymor studied generated ______ (with sharper edges).
larger plaques
the mutation seymor studied also helped the viruses
lyse their hosts earlier.
benzor saw that II- mutants can infect E coli K but
cannot get that strain of bacteria to
make (more) viral particles
benzer concluded (3)
-A gene consists of different parts and each can mutate
-Gene is a linear arrangement of nucleotides and
recombination between different mutable parts can generate
a normal, wild-type allele
-A gene only performs its normal function if all components
are wild-type
How a Genotype Causes a Phenotype
Scientists learn about normal gene function by looking at
the disrupted, broken or diseased state
Archibald Garrod studied
a metabolic disease (alkaptonuria)
after studying alkaptonuria garrod determined
that the sick family members lack an enzyme due to a mutation
beadle and tatum proposed
One Gene, One Enzymes in 1940s
