---
title: "Horizontal Gene Transfer: Uptake, Contact and Delivery"
description: "Bacteria acquire genes from other cells by taking up free DNA, by direct contact through a pilus, or by delivery inside a phage particle. Because transfer crosses species lines, a bacterial family tre"
canonical: https://lightmysky.com/learn/science/horizontal-gene-transfer-uptake-contact-and-delivery-mt_mrmn0_nQf7
source: https://lightmysky.com/learn/science/horizontal-gene-transfer-uptake-contact-and-delivery-mt_mrmn0_nQf7.md
retrieved: 2026-09-12
---

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# Horizontal Gene Transfer: Uptake, Contact and Delivery

Bacteria acquire genes from other cells by taking up free DNA, by direct contact through a pilus, or by delivery inside a phage particle. Because transfer crosses species lines, a bacterial family tree drawn from one gene can disagree with one drawn from another.

Subject: Science · Area: Microbiology · Ages 20 to 21
Page: https://lightmysky.com/learn/science/horizontal-gene-transfer-uptake-contact-and-delivery-mt_mrmn0_nQf7

## Ready when they can

- Distinguishes the three routes by what carries the DNA and what the recipient must do.
- Designs a test that tells one route from another, such as separating cells with a filter.
- Explains why transfer complicates a phylogeny built from a single gene.

## Lesson: Three ways to borrow genes

Bacteria reproduce asexually, yet their genomes stay restless. Transformation lets a competent cell pick up free DNA spilled by dead neighbors. Transduction happens when a phage accidentally packs host DNA and injects it into the next victim. Conjugation builds a pilus bridge and sends a plasmid copy across to a living partner. Three routes, three carriers: the surroundings, a virus, and direct contact.

Telling the routes apart means asking what each one physically needs. A filter fine enough to block cells stops conjugation but leaves the other two running. Destroying all free DNA stops transformation only. Only transformation needs the recipient to pull naked DNA inside, so competence matters there and nowhere else.

**Example.** Because transfer crosses species lines, trees can disagree. A family tree drawn from one transferred gene tells the travels of that gene, which rode a virus or a bridge, while the cells themselves stayed put. Trusting one gene for the history of the cells is how the confusion starts.

**Tip.** To name a route, ask what carried the DNA and what the recipient had to do.

**Recap.** Carriers differ, tests split them, and borrowed genes rewrite family trees.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Bacteriophages as Predators and as Laboratory Tools](https://lightmysky.com/learn/science/bacteriophages-as-predators-and-as-laboratory-tools-mt_vOnjSpXjrj)

## Opens up

- [Plasmids, Mobile Elements and How Resistance Spreads](https://lightmysky.com/learn/science/plasmids-mobile-elements-and-how-resistance-spreads-mt_Vk0qOY64qv)