G11 Hugo De Vries, Mutations, and Mutagenesis

explain the mechanism of chromosome, gene mutation.
11.2.3.13 to study the

theory of mutation of Hugo De Vries and mutagenesis and its causes.
Success Criteria
Identify and explain the causes, types and mechanisms of genetic mutations.
Discuss the features of Hugo De Vries theory of mutations.
Compare points in favor and against Hugo De Vries theory.
Differentiate between spontaneous and induced mutations.
Define Mutagenesis

CIE Biology Jones
p387-389 (little bit)

Not Required –Interest Only Mutagenesis (Chemical basis)
https://www.slideshare.net/sreerajsree/spontaneous-and-induced-mutations

Not required – Interest only
Chimera Mutations
Images - https://www.ranker.com/list/chimera-animals/mariel-loveland?utm_expid=16418821-388.8yjUEguUSkGHvlaagyulMg.0&utm_referrer=https%3A%2F%2Fwww.google.kz%2F
Information --https://en.wikipedia.org/wiki/Chimera_(genetics)

appear (mutation), but they may be selected against due to

not being as ‘fit to survive..

Punctuated equilibrium is similar to De Vries Discontinuous Evolution by Mutation Theory

dwarfing of legs
New species originate as a result of discontinuous

variation that appears suddenly and may be passed to offspring.

Continuous Discontinuous
Slow and gradual fast and jerky
Change over time change over time

of the first geneticist.

He is known mainly for suggesting the

concept of 
Genes
Rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel’s work
Introducing the term “mutation“
Developing a mutation theory of evolution.
https://en.wikipedia.org/wiki/Hugo_de_Vries

Evening primrose
Oenothera lamarckiana

his research
without knowing about Mendel’s work,
but he came

to the same conclusions.
He first published his work without
mentioning Mendel, but later updated
his work to include him as a source.

De Vries – studied Evening Primrose,
a plant that would have significant
phenotypical differences such as leaf shape
and plant sizes. Some offspring with a ‘mutation’ would pass this on to their progeny (offspring), which De Vries decided was a new species.

He called this discontinuous variation – Defined as species that evolve from other species through, sudden large changes of character traits.

It is now known that the unusual variations, ‘mutations’ observed from his plant Oenothera lamarckiana, were due to aberrant chromosomal segregations and NOT to mutation of specific genes.

Evening primrose - Oenothera lamarckiana

Darwin’s Book the “Theory of Pangenesis”, he suggested that inheritance

of specific traits in an organism comes in particles. He called the particles ‘pangenes’ which 20 years later was shortened to ‘genes’
He also agreed with Darwin that organisms change over time, but postulated that they did large changes over time were discontinuous and called them, saltationism. Remember saltatory conduction of action potential?
He took a wild primrose from a field and grew plants that had many new variations. He called the changes mutations. Later it would be found that the variety was due plants being polypoloidy, not muations.
He inspired Thomas Morgan to study mutations in fruit flies.
He was the first to suggest the occurrence of recombination between homologous chromosomes. “Crossovers”

I of
Meiosis
Errors of DNA Chromosome
Deletion

Part of a X is left off
Insertion / Duplication
Part of a X breaks off and is reinserted
on a sister chromosome
Inversions
Part of a X breaks off, flips, and then
reinserts backwards
Translocations
Part of a X breaks off and is added
to a different chromosome.

Errors of DNA-base pairing
Point mutation: SUBSTITUTION
exchange of one nitrogen base for another. May or may not change one amino acid –
Frameshift mutation – INSERTION OR DELETIONS
addition or deletion of one nitrogen base. Changes the entire reading frame of the protein.

GENE Mutation

Chromosomal (X) Mutation

SUBSTITUTION

INSERTIONS: DELETIONS

The dog bit the cat
The dog bit the car
AAA TTT CCC GGG
AAA TTA CCC GGG

The dog bit the cat
The dog itt hec at
AAA TTT CCC GGG
AAA TTC CCG GG

Monosomy X
Disomy XX (normal)
Trisomomy XXX
Polyploid XXXXX

a gene or chromosome
Spontaneous – naturally occurs from errors in

replication or replication repair.
Induced – exposure to radiation or mutagens (things that cause mutations – carcinogens…)

Frame-shift (GCAT)
(i) substitution, deletion, insertion
(b) Chromosomal Mutations
(ii) insertion, deletion,

translocation, duplication
(c) Unrepaired DNA replication errors – p53 defected
Induced Mutagenesis
(a) Environmental DNA damage – radiation, free
radicals…