speaker: xudong zou time: 17 th april, 2014 peking university shenzhen graduate school 1
TRANSCRIPT
1
The Origination of New genes
Speaker: Xudong ZouTime: 17th April, 2014
Peking University ShenZhen Graduate School
2
Outline
Background
Molecular mechanisms Exon shuffling Gene duplication Lateral gene transfer Gene fusion/fission De novo gene origination
Summary
3
Outline
Background
Molecular mechanisms Exon shuffling Gene duplication Lateral gene transfer Gene fusion/fission De novo gene origination
Summary
4
In an ancient Chinese legend, the first Chinese emperor Yande (3,000 BC) brother to the Yellow-Emperor, had apretty princess named Jingwei.Like other legendary southern Chinese
goddesses, Jingwei liked to swim. Unfortunately, she drowned in the East China Sea. She was reincarnated into a beautiful bird, who, to save others from possible tragedy, carried soil and stones in an attempt to fill in the ocean.
The legend of Jingwei
5
Manyuan Long and the Jingwei gene
Manyuan LongDepartment of Ecology & EvolutionBiological Sciences Collegiate DivisionUniversity of Chicago
JingweiThe first young gene described in the early 1990s. It is a very young gene that if we set 1 million years as an age unit, the common old genes are often 1000~3000 years old, while Jingwei is 2 years old.
6
1950s--
In 1953, DNA double helix
In 1966, Richard Lewontin and Huby found that natural selection can’t explain molecular evolution
In 1968, Motoo Kimura introducing neutral theory of molecular evolution
1990s--
In 1993, Manyuan Long described the Jingwei gene, open a new field to study the origination and evolution of new genes
7
CHARLES H. LANGLEY
In 1990, Manyuan Long joined Langley’s lab and investigated degree of fitness of neutral theory on DNA.
Michael Ashburner told that gene Adh of D. melanogaster was a pseudogene.
Long found that almost all of the mutation occur at the third site of a codon. Means it may be a real gene rather than a pseudogene.
Long confirmed the complex processes of the origination of this gene and named it Jingwei.
8
Outline
Background
Molecular mechanisms Exon shuffling Gene duplication Lateral gene transfer Gene fusion/fission De novo gene origination
Summary
9
Exon shufflingTwo or more exons from different genes can be brought together ectopically, often mediated by transposons, or the same exons can be duplicated to create new exon-intron structure.
Long interspersed element(LINE) Helitron Long-terminal repeat retrotransposons
Examples:fucosyltransferase, jingwei, Tre2
Transposon:
Long MY, et al. Nat Rev Gent. 2003
10
Exon shuffling
Yellow-emperor Adh: a pseudogene
Origination of jingwei from the following two genes:
Sphinx structureLong MY, Science. 1993Long MY, et al. Nat Rev Gent. 2003
11
Gene duplicationThis classical model creates a duplicate gene that can evolve new functions, whereas the ancestral copy maintain its original functions.
Examples:CGβ, Cid, RNASE1B
New duplicated genes under positive selection and evolve new functions
Gene duplication may be three variable tpyes: Complete gene duplication, partial gene duplication and dispersed gene duplication.
Long MY, et al. Nat Rev Gent. 2003Cardoso-Moreira M and Long MY. 2004
12
Gene duplication
RNASE1 and RNASE1B were generated by recent duplication from other old world monkey.
RNASE1 has not changed since duplication, while RNASE1B accumulated many substitutions.
The ability to digesting double-strand RNA of RNASE1, lost in RNASE1B
Zhang J, et al. Nature Genet. 2002
13
Lateral gene transfer
Examples:acytylneuraminate lysase, Escherichia coli, mutU and mutS
Lateral gene transfer is the gene tranferred between different organisms. Often in Prokaryotes, rare in eukaryotes.
Long MY, et al. Nat Rev Gent. 2003Cardoso-Moreira M and Long MY. 2004
14
Gene fusion/fission
Examples:Fatty-acid synthesis enzymes,Kua-UEV, Sdic
Two adjacent genes can fuse into a single gene or a single gene can split into two single genes by mutations on stop codon or initial codon.
Long MY, et al. Nat Rev Gent. 2003
15
De novo origination
Examples:AFGPs, BC1RNA, BC200RNA
De novo genes refer to events, where a coding region originates from a previously non-coding region.
Long MY, et al. Nat Rev Gent. 2003Cardoso-Moreira M and Long MY. 2004
16
Outline
Background
Molecular mechanisms Exon shuffling Gene duplication Lateral gene transfer Gene fusion/fission De novo gene origination
Summary
17Long MY, et al. Nat Rev Gent. 2003