Biological Recombination In genomes, in genes, in proteins

Preface: Fu et al ‘02 Transposon? Ac and Ds? Retrotransposon? Genetic length vs. physical length? Recombination higher among genes? ?

What I’ll Cover Reasons and mechanisms Rates and sites Within-protein

Why recombine? Cui bono?

Kondrashov’s Theory of Sex Kondrashov, A. S., Nature 336, (1988). X X X X =

DSB model See Szostak et al, Cell 33, (1983).

DSB model Limited crossover Full crossover

Transposons: cut and paste Davies et al, Science 289 (2000)

Retrotransposons: copy and paste gagprot DR 334 DR 334 intrt Yeast Ty element, 6 kb cDNA mRNA

Measuring recombination 1911: Alfred Sturtevant invents the map unit A story every graduate student should remember.

Where does recombination occur? Thuriaux, P., Nature 268, (1977).

Rates in gene-rich regions Fu et al, PNAS 99:2, (2002) … ~100kb transposon nest … 0.06 cM, 108 kb Ac cM 6.5 kb 0.25 cM, 11.6 kb 0.24 cM 6.7 kb Ac6087 Ac6067 bz Ac2094

Variability of Recomb. Rates McKim, K., Ann. Rev. Gen. 36, (2002).

Recombination inside genes Alternative splicing Mobile introns And a gene that will blow your mind.

Alternative splicing Roberts et al, Curr. Op. Chem. Bio. 6, (2002).

Intron mobility Some introns “home” Introns are gained and lost constantly Introns define exons –Are exons domains? –Selective pressure?

jingwei: the Frankengene Llopart et al, PNAS, 99:12, (2002).

Acknowledgments Recombination group and Frances Chris Adami Shoulders of various giants

And there’s more… Immune-system domain shuffling Inteins