Transferencia horizontal de genes Horizontal transfer contrasts with

Transferencia horizontal de genes Horizontal transfer contrasts with vertical gene transfer in which genes move from mother cell to daughter cell. In fact, it has been estimated that nearly 20% of the E. coli genome originated from horizontal transfers. Horizontally transferred segments of DNA can often be detected because they have significantly different GC ratios (the ratio of guanine–cytosine base pairs to adenine–thymine base pairs) or codon distributions (codon bias, Section 6. 17) from those of the host organism.

Assembly of new combinations of genes, increasing of diversity and speed up of evolution

Replica ADN Integra por recombinación homóloga

Recombinación homóloga

Transformación bacteriana

Natural >12 genes involucrados Competencia Regulada por quorum sensing Uptake ss. DNA Artificial Uptake ss. DNA, d. DNA Conviene hacer rec. D Electrotransfor mación Ca. Cl 2

Conjugación bacteriana

Conjugación

Conjugación

• Mpf • Dtr

Conjugación: Hfr • Formación Hfr

Conjugación: transferencia de genes cromosomales por Hfr

Conjugación: factores prima Prime factors • formation

TP Transformación y Conjugación

Transformación B. subtilis JH 642 (trp. C 2 phe. A 1) Competencia natural In Bacillus subtilis, competence develops post-exponentially and only in certain media. In addition, only a minority of the cells in a competent culture become competent, and these are physiologically distinct. Replicativo en E. coli Suicida en B. subtilis amy. E-cat: Cm. R β-gal Selección simples y dobles cross-over

Transformación E. coli DH 5α Competencia inducida químicamente Replicativo en E. coli Amp. R

Conjugación XLI-blue (rec. A 1, end. A 1, gyr. A 96, thi-1, hsd. R 17, sup. E 44, rel. A 1, lac [F', pro. AB+, lac. Iq, lac. Z 15: : Tn 10 (Tet. R)] MC 4100 (sup. E 44, lac. U 169, hsd. R 17, gyr. A 96, rel. A 1 thi (lac-pro. AB) Sm. R Exconjugantes: Sm. R y Tet. R

Seminarios