Two primary sources of all genetic variation


11 Δεκ 2012 (πριν από 8 χρόνια και 7 μήνες)

263 εμφανίσεις

Chapter 9: How Genes and Genomes Evolve

Two primary sources of all genetic variation: mutation and

Primarily look at:

A. Prokaryotic and their overlap with
genetic engineering/viruses:
All mutations are passed on.

B. eukaryotic systems, meiosis and genetic
recombination. Only germ cell pass on the
traits Fig. 9.2
Mutation with in a gene:

Mutation with a regulatory sequence:

Duplication / deletion:


Transfer via a viral vector:

Gene mutations will follow a “force”. Lactose tolerance follows the domestication of
cattle Fig. 9.6

Bacillus subtils: . Fig. 9.8
77 genes in a larger transporter family

about 2,000 have no clear family

Genome duplication: Common in plants… Why? Lets review plant biology… Bio 106

Exons can also create novel genes: Fig. 9.13, 9:14 Shuffling, etc..

Mobile genetic elements and the bump on my head…

Bacterial Sidebar: Recall from 107..Bacterial also alter genome via:
In addition to intrinsic mutation, ba
can attain greater diversity via uptake of
• Conjugation: Fertility plasmid (F
plasmid): pili to bridge and rolling
• Transformation: rare and often not
functional as “naked DNA (w/out
protective proteins) is often damaged.
But…. Commonly used in lab and is
known as: genetic engineering
• Transduction: Use of a viral

Eukaryotic: Revisit..

Crossing over: Results in genetic variation
with no “mutation.”
Or uptake of DNA through any of the
above mentioned three vectors.

Single cross over (swap of whole portion of
chromosomes between analogous pairs.

2. Genome Duplication: Prev. Discussed..

3. Exon Shuffle:

9.9: Un-equal C.O.

9.12 Polyploidy… From spindle, etc..

Genes with low variability: High Conserved: SSU Proteins

Leanest Vertebrate Genome: Fugue: Some basic biology about the fish…

Fig. 9.29: Composition of the Human Genome: See model…
a. LINES (20%) : Long Interspersed Nuclear Elements:

b. SINES (13 %) : Short Interspersed Nuclear Elements

c. Retroviral Elements (9 %): Retro-transposons…HIV gene?

d. DNA Only Transposons: (3%).

A-D are all mobile genetic elements: Viral Parasites…Look at Amoeba and its
bloated genome…

e. Simple Repeats (1%):

f. Segment Duplications: (6 %) DNA transposons:

E/F: VNTRs, microsatellites: Big in forensic and CODIS: Likely polymerase or other
enzyme mistakes…

CODIS is short for: Combined DNA Index System…FYI…

A-F are repeated sequences (short…AGAGAGAG. Or log (copied gene, etc).

G-I are no repeated and their unique sequences suggest DNA coding or other information
(as opposed to molecular parasite, random garble, etc. )

g. Non repetitive DNA (not intron or exon) Regulatory (28 %)? Most
intriguing…possible regulatory.

h. Introns (20 %) Crossing over site, splicing for novel protein products…

i. Genes (1.5%). Surprisingly small amount of DNA…

Chromosome Fly-over:….