At Its Most Basic Level, Biotechnology Includes Animal and Plant Breeding

DNA Technology

Biotechnology

Biotechnology can be defined as the use of technology to control biological processes as a means of meeting societal needs

At its most basic level, biotechnology includes animal and plant breeding

Biotechnology is a broad category that currently encompasses:

The production of transgenic organisms

Techniques to clone animals

The reprogramming of cells to become different types of cells

The use of biotechnology in forensics

A transgenic organism is an organism whose genome carries one or more genes from another species

Many biotechnology products are produced within transgenic organisms

Genetic Engineering

The production of transgenic organisms makes use of recombinant DNA technology

This makes use of enzymes normally produced in bacteria

Restriction enzymes

DNA ligase

Scientists have

genetically engineered bacteria to mass-produce a variety of useful chemicals, from cancer drugs to pesticides, and

transferred genes from bacteria to plants and from one animal species to another

Recombinant DNA Techniques

Bacteria are the workhorses of modern biotechnology

To manipulate genes in the laboratory, biologists often use bacterial plasmids - small, circular DNA molecules that duplicate separately from the larger bacterial chromosome

DNA from any organism (including humans) can be inserted into plasmid DNA

Plasmid DNA is isolated from bacteria

The transgenic bacteria can then produce the gene products desired

Restriction enzymes act as molecular scissors, recognizing specific DNA sequences and cutting them

Cutting both the target DNA and the plasmid DNA with the same restriction enzyme gives complementary “sticky ends”, allowing splicing of the target DNA into the plasmid

This produces recombinant DNA

Gel Electrophoresis

Cutting DNA gives a variety of DNA fragments

We often need to separate those fragments using gel electrophoresis

This method separates the DNA fragments based on length

The same recombinant DNA techniques are used to make other transgenic organisms

Like golden rice or cassava enriched for beta carotene to help prevent Vitamin A deficiency and its resulting blindness

or the Innate potato that resists bruising and produces less of a cancer-causing chemical when fried

or the Arctic apple that resists turning brown when sliced or bruised

3/20/15 The Food and Drug Administration said that genetically engineered non browning apples and bruise-resistant potatoes were as safe and nutritious as their conventional counterparts

or transgenic goats producing important proteins in their milk

or even cows producing hypoallergenic milk

2-3% of babies are allergic to cow milk and experience diarrhea and vomiting

Human Gene Therapy

Human gene therapy is intended to treat disease by introducing genes into an afflicted person

In cases where a single defective gene causes a disorder, the mutant version of a gene may be replaced or supplemented with the normal allele

This could potentially correct a genetic disorder, perhaps permanently

In other cases, genes are inserted and expressed only long enough to treat a medical problem

Despite all of the promise associated with this technology, there have been few successes

2000-2011 - gene therapy cured 22children with severe combined immunodeficiency (SCID)

These patients had no immune system, requiring them to remain isolated within protective “bubbles”

However, there were some problems as well

DNA Profiling and Forensic Science

DNA profiling

is the analysis of DNA samples to determine whether they come from the same individual and

has rapidly transformed the field of forensics

To produce a DNA profile, scientists compare sequences in the genome that vary from person to person

DNA Profiling Techniques - PCR

The polymerase chain reaction (PCR)

is a technique by which a specific target segment of DNA can be amplified quickly and precisely, and

permits scientists to obtain enough DNA from even minute amounts of blood or other tissue to allow a DNA profile to be constructed

Short Tandem Repeat (STR) Analysis

How do you prove that two samples of DNA come from the same person?

Repetitive DNA makes up much of the DNA that lies between genes in humans

Short tandem repeats (STRs)are short sequences of DNA tenderly repeated many times in the genome

DNA profiling can also be used to confirm paternity

Genomics

Genomics is the study of complete sets of genes (genomes) of organisms

The Human Genome Project

Begun in 1990, the Human Genome Project was a massive scientific endeavor to

determine the nucleotide sequence of all the DNA in the human genome and

identify the location and sequence of every gene

More than 99% of the genome had been determined to 99.999% accuracy

About 3 billion nucleotide pairs were identified

About 21,000 genes were found

About 98% of the human DNA was identified as noncoding

Some noncoding DNA is made up of gene control sequences (promoters, enhancers, and microRNAs)

Some noncoding regions include introns and repetitive DNA

Some noncoding DNA is important to our health, with certain regions known to carry disease-causing mutations

The function of most noncoding DNA is unknown

The DNA sequences of ancient species have also been determined, including our relatives

In 2013, scientists sequenced the entire genome of a 130,000-year-old female Neanderthal (Homoneanderthalensis)

Scientists used DNA extracted from a toe bone found in a Siberian cave to identify a new species (Homodenisovans) related to modern humans