DNA Extraction Lab: Strawberry – Background: The long, thick fibers of DNA store the information for the functioning of the chemistry of life. DNA is present in every cell of plants and animals. The DNA found in strawberry cells can be extracted using common, everyday materials.
Strawberries are soft and easy to pulverize. Strawberries have large genomes; they are octoploid, which means they have eight of each type of chromosome in each cell. Thus, strawberries are an exceptional fruit to use in DNA extraction labs and strawberries yield more DNA than any other fruit (i.e. banana, kiwi, etc.).
We will use an extraction buffer containing salt, to break up protein chains that bind around the nucleic acids, and dish soap which helps to dissolve the phospholipid bilayers of the cell membrane and organelles. This extraction buffer will help provide us access to the DNA inside the cells.
- heavy duty quart ziploc bag
- Strawberry
- Table salt
- Shampoo (look for sodium lauryl sulfate as a first ingredient)
- Water
- Cheesecloth or similar loose woven fabric
- Funnel
- 50mL vial / test tube or similar container
- 500 mL beaker or mason jar
- glass rod, popsicle stick, wooden skewer or toothpick
- chilled (refrigerated or briefly frozen) isopropyl alcohol
Warning: Isopropyl alcohol is a skin irritant, and inhaling or consuming it can make you sick. Use in a well ventilated space. Alcohols are also flammable and the vapors can ignite. Keep away from open flame. Procedure:
- Gather all materials.
- Prepare the DNA extraction buffer.
In 500 mL beaker add
- 400mL (1 ¾ cups) water
- 50mL (3 Tablespoons + 1 teaspoon) shampoo
- 5mL (2 teaspoons) table salt
Slowly invert the bottle to mix the extraction buffer.
- Place one strawberry in a Ziploc bag.
- Smash/grind up the strawberry using your fist and fingers for 2 minutes. Careful not to break the bag!
Why? The physical smashing breaks the plant’s cell walls and allows the cytoplasm to leak out.
- Add 10mL (2 teaspoons) of extraction buffer (salt and soap solution) to the bag.
- Kneed/mush the strawberry in the bag again for 1 minute.
Why the detergent? The soap breaks down the lipids (fats) in the phospholipid bi-layers of the cell membrane and nuclear membrane. This releases the contents from the cell and the chromosomes containing DNA from the nucleus.
- Assemble your filtration apparatus as shown to the right.
- Pour the strawberry slurry into the filtration apparatus and let it drip directly into your test tube.
Why? Filtering strains all the large cellular junk out of the mix. The DNA, still tightly wound, is so small it slips through with the liquid and into the test tube. Caution! From this stage onward, you must be careful not to agitate the mixture.
Gently Slowly pour 20mL (1 Tablespoon + 1 teaspoon) cold alcohol down the inside wall of the test tube to form a separate, clear layer on top of the cloudy strawberry mixture below (You should see small wisps of gel-like material forming above the boundary.) OBSERVE
Why? The polar/non-polar boundary layer causes the DNA to precipitate. The tiny bits of wispy junk floating in the alcohol just above the boundary layer is DNA.
- Dip the glass rod or wooden stick into the tube where the strawberry extract and alcohol layers come into contact with each other. OBSERVE
- If the procedure worked really well (it often doesn’t) you will get long strands of DNA forming, sometimes more than an inch long! Using the bamboo skewer or toothpick, gently wind up the precipitated DNA.
- As you gently lift the skewer or toothpick out of the container after winding, it will carry long strands of a mucus-like substance that looks like “boogers.” That’s concentrated DNA, just like they do it on CSI 😉
If it didn’t work perfectly, don’t despair. Most people see the wispy stuff, but you have to get a bit lucky to get the long strands to form References and Resources: https://www.scientificamerican.com/article/squishy-science-extract-dna-from-smashed-strawberries/ https://science.wonderhowto.com/how-to/extract-dna-from-strawberry-with-basic-kitchen-items-0140302/ https://www.stevespanglerscience.com/lab/experiments/strawberry-dna/ Video: https://youtu.be/vPGKv53zSRQ Video: https://youtu.be/usaE_XZx-a8
Contents
- 1 How many sets of DNA do bananas have?
- 2 Why is it harder to extract human DNA?
- 3 Do we share 50% of DNA with a strawberry?
- 4 Why do people extract DNA from fruit?
- 5 Which fruit extracts the most DNA?
- 6 Why do bananas have less DNA?
- 7 How do you get the most DNA out of a strawberry?
Why do strawberries have 8 sets of DNA?
Uncovering the origins of the cultivated strawberry Until now, little has been known about the evolutionary origins of the cultivated garden strawberry. Whereas most species, including humans, are diploid with two copies of the genome – one copy from each parent – strawberry is an octoploid, with eight complete copies of the genome that were contributed by multiple, distinct parental species.
In a new study published in Nature Genetics, researchers now unveil how the strawberry became an octoploid, as well as the genetics that determine important fruit quality traits. What researchers uncovered is a complex evolutionary history that started long ago on opposite sides of the world. “For the first time, analysis of the genome enabled us to identify all four extant relatives of the diploid species that sequentially hybridized to create the octoploid strawberry,” said Patrick Edger, MSU assistant professor of horticulture and co-author on the paper.
“It’s a rich history that spans the globe, ultimately culminating in the fruit so many enjoy today.” These four diploid species are native to Europe, Asia and North America, but the wild octoploids are almost exclusively distributed across the Americas.
- The results presented in the paper suggest a series of intermediate polyploids, tetraploid and hexaploid that formed in Asia, prior to the octoploid event that occurred in North America, involving the hexaploid and a diploid species endemic to Canada and the United States.
- This makes the strawberry relatively unique as one of only three high-value fruit crops native to the continent.
Breeders began propagating these octoploids around 300 years ago. Since then, they have been used around the world to further enhance variety development. However, Edger hypothesized that — as with several other polyploids — an unbalanced expression of traits contributed by each diploid parental species, called subgenome dominance, would likely also be present in the octoploid strawberry.
He was right. “We uncovered that one of the parental species in the octoploid is largely controlling fruit quality and disease resistance traits,” Edger said. “Knowing this, as well having identified the genes controlling various target traits, will be helpful in guiding and accelerating future breeding efforts in this important fruit crop.” The genomic discoveries provided by this study will advance the trait selection process, bringing about a more precise method of breeding for this important worldwide crop.
The genome will enable studies that were previously unthinkable in strawberry, and will be a catalyst for tackling difficult breeding and genetics questions. “Without the genome we were flying blind,” said Steven Knapp, UC-Davis plant scientist and study co-author.
- I remember the first time I saw a visualization of the assembled genome, which went from a complex jumble of DNA molecules of 170 billion nucleotides to an organized and ordered string of 830 million base pairs.
- That was a special moment that changed everything for us in strawberry.” Knapp said that, historically, scientists studying complex biological phenomena in strawberry have tended to focus on diploid relatives because of the complexity of the octoploid, even though genetic analyses in the octoploid are actually straightforward once one has a good road map.
“We have been on a crusade to shift the focus in the basic research community to the commercially important octoploid,” Knapp said. “The wild octoploid ancestors, together with cultivated strawberry, provide a wellspring of natural genetic diversity to support biological and agricultural research.” Traditional breeding has been highly successful in strawberry, yielding outstanding modern cultivars that have been the catalyst for expanding production worldwide.
As with other crops, many challenges remain that will require breeders to continually redesign cultivars and introduce genes from wild species and other exotic sources to meet new challenges. The genome is an essential vehicle for applying predictive, genome-informed approaches in strawberry breeding and cultivar development.
For the U.S., improved varieties could provide a boon to an already-thriving business. The U.S. is the global leader in strawberry production, a yield comprising roughly one-third of the world’s total. In 2016, the country produced more than 1.5 million tons.
The sequencing and analysis of the cultivated strawberry genome, exposing a wealth of new information about its origin and traits, is the product of an international team supported by MSU AgBioResearch, UC Davis, the United States Department of Agriculture, the California Strawberry Commission and the National Science Foundation.
(Note for media: Please include a link to the original paper in online coverage: ) : Uncovering the origins of the cultivated strawberry
Do strawberries or humans have more DNA?
Each little piece of a living thing, known as a cell, has DNA in it. In humans each of these cells have 2 copies of the DNA, but in strawberries each of these have 8 copies of the DNA (scientists call this octoploid). That means strawberries have 4 times as many copies of DNA as humans, making it 4 times easier to see!
Why do strawberries have 56 chromosomes?
Unwinding the past – While the modern strawberry’s chromosome collection is genomically complex, its fundamental genome is one of the simplest among crop plants. The strawberry of commerce is octoploid (2 n = 8× = 56; seven chromosome sets and eight chromosomes per set, 56 total), meaning that each cell contains remnants of four separate ancestral diploid subgenomes that underlie strawberry’s form and function.
Examination of the origins of these four subgenomic complements began early in the 20th century, with study of meiotic pairing 9, 10, suggesting that an ancestor of the extant diploid species F. vesca was a contributor to the octoploid genome. Small hints of the identity of other subgenome donors came from genetic analyses and various reconstructions 11, 12, along with some molecular 13 and cytological 14 data that provided critical clues.
Several of these avenues suggested that an ancestor of F. iinumae was at least one of the other subgenome donors. As pointed out by Edger et al.15, the genome is an allopolyploid, arising from multiple rounds of gametic nonreductions and cross pollination events.
Today the resulting subgenomes continue to behave as separate blueprints interpreted simultaneously to define the assembly and function of a common complex structure. The multiple-blueprint problem has hampered simple genetic analyses, as if a locus was mapped in a diploid genome, it may reside in any, or all, of the subgenomes that comprise the modern octoploid strawberry.
To make matters worse, strawberry is highly heterozygous, making it difficult to distinguish between homoeologous and paralogous gene copies. The recently published “Camarosa” sequence strengthened the evidence identifying the other genomic constituents in commercial strawberry.
The work agrees with earlier findings that F. iinumae and F. vesca are closest descendants to two of the four subgenome donors. But there is great diversity within F. vesca, a species that covers the northern hemisphere. The authors were able to narrow down the subspecies to F. bracheata, consistent with other findings that suggest this genotype contributed the maternal genome 16,
The authors identified genome sequence most closely resembling modern day F. nipponica, implying that ancestors of this species (that were sympatric with F. iinumae in Japan) gave rise to proximal tetraploid genotypes in neighboring China. The analysis also identified sequence most resembling the Eurasian genotype F.
What are two reasons why strawberries were specifically selected for DNA extraction?
Ripe strawberries are an excellent source for extracting DNA because they are easy to pulverize and contain enzymes called pectinases and cellulases that help to break down cell walls. And most important, strawberries have eight copies of each chromosome (they are octoploid), so there is a lot of DNA to isolate.
Why do bananas extract more DNA than strawberries?
Strawberries are octaploid, which means they have 8 copies of each type of chromosome inside the nucleus of each cell. Strawberries have 7 chromosomes, so they have a total of 56 chromosomes in every cell. Bananas are triploid, which means they have 3 copies of each type of chromosome inside the nucleus of each cell.
How many sets of DNA do bananas have?
Complicating matters, some bananas have the usual two sets of chromosomes, whereas others have three sets or more, suggesting at least some modern bananas are hybrids that resulted from the interbreeding of two or more varieties, or even different species.
Why is it harder to extract human DNA?
Abstract. Retrieving DNA from highly degraded human skeletal remains is still a challenge due to low concentration and fragmentation, which makes it difficult to extract and purify.
You may be surprised to learn that 60 percent of the DNA present in strawberries is also present in humans.
Who has 52 chromosomes?
List of organisms by chromosome count
Organism (Scientific name) | Chromosome number |
---|---|
Spectacled bear (Tremarctos ornatus) | 52 |
Platypus (Ornithorhynchus anatinus) | 52 |
Upland cotton (Gossypium hirsutum) | 52 |
Sheep (Ovis aries) | 54 |
How many genders do strawberries have?
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- Estoy de Acuerdo / I agree Collapse ▲ Strawberry flower morphology and seed set Strawberry flowers have both male and female parts on each bloom.
The male parts include the pollen carrying portion of the flower (highlighted in blue) and pollinators must come into contact with this area to collect pollen grains. The female parts of the flower (highlighted in pink) must individually receive pollen grains to attain complete pollination. Strawberry flower. Photo: Jeremy Slone Lack of complete pollination in each pistil (female flower part) can result in smaller or misshapen berries, meaning reduced yield of marketable fruit. Poorly pollinated berry (left) and a misshapen berry (right). Photo: Jeremy Slone The actual berry forms from each pistil developing into an individual “seed’ that is actually an individual fruit, called an achene. The fleshy red part of the strawberry is rather an enlarged receptacle that holds the achenes ( Poling, 2012 ).
Berry development from each pistil being pollinated into individual achenes. Photo: Jeremy Slone As seen in the photo below, there are many ways for pollen to be transferred within the flower and unlike some crops, strawberries are self-fertile. However, maximum yields are possible with a combination of self-pollination (pink), wind (blue), and insects (green).Although flowers are capable of self-pollinating, each pistil must receive pollination, and studies have shown that self-pollination and wind-blown pollen are often not sufficient to completely pollinate a flower.
Different modes of pollination on each flower. Photo: Jeremy Slone References:
Klatt, B.K., Holzschuh, A., Westphal, C., Clough, Y., Smit, I., Pawelzik, E., & Tscharntke, T. (2014). Bee pollination improves crop quality, shelf life and commercial value,R. Soc. B, 281, Wietzke, A., Westphal, C., Kraft, M., Gras, P., Tscharntke, T., Pawelzik, E., & Smit, I. (2016). Pollination as a key factor for strawberry fruit physiology and quality, Berichte Aus Dem Julius Kühn-Institut, 183, 49–50. Zebrowska, J. (1998). Influence of pollination modes on yield components in strawberry (Fragaria x ananassa Duch.), Plant Breeding, 117 (3), 255–260.
(Written by Jeremy Slone, August 2016)
Why do people extract DNA from fruit?
Activity 1 – DNA Extraction – We will extract DNA from fruit to investigate how it looks and feels. This procedure is similar to what scientists have to do before they can use the information contained in this DNA. This information can be used to improve crops so that they are more resistant to disease, insect invasion or changes in climate.
Figure 1 | Figure 2 |
Which fruit extracts the most DNA?
Choose a fruit, any kind will do. However, kiwi, mango and strawberry have been found to yield the most DNA.
Why do bananas have less DNA?
The ripe and over ripe bananas produced a smaller amount of DNA because the cells that stick the nutrition break down and begin to decompose when it begins to ripen.
How do you get the most DNA out of a strawberry?
WHAT DOES STRAWBERRY DNA LOOK LIKE? – Each individual cell in an organism has a copy of the DNA pattern used to reproduce that cell. Usually, the DNA is combined within the cell, so you can’t see it. But when you create a mixture of dish soap and salt, and mix it with crushed strawberry pulp, it helps break down the strawberry cells into individual parts.
Crushing the strawberries helps release the DNA into the solution. The purpose of the salt is to help the strawberry DNA remain undissolved in water. Once the alcohol is added to the strawberry pulp, it encourages the DNA strands to rise to the top and bind together. This is where you can see them together in one long, clear strand.
It’s fascinating to see the strawberry DNA strands up close and personal! It doesn’t take long to extract DNA from strawberries. Just follow our simple instructions below.
Do strawberries have 8 sets of chromosomes to thank for their survival?
Hidden beneath the surface of the treasured strawberry is a unique branch of the evolutionary tree, where eight sets of chromosomes are better than two Credit: Jasmina007/Getty Images
How many sets of DNA do strawberries have?
Strawberries are octoploid, meaning that they have eight copies of each type of chromosome.
How did strawberries become octoploid?
Cultivated strawberry emerged from the hybridization of two wild octoploid species, both descendants from the merger of four diploid progenitor species into a single nucleus more than 1 million years ago.
How many base pairs are in strawberry DNA?
Woodland strawberry genome sequenced An international research consortium has sequenced the genome of the woodland strawberry, according to a study published in the Dec.26 advance online edition of the journal Nature Genetics, The development is expected to unlock possibilities for breeding tastier, hardier varieties of the berry and other crops in its family.
- We’ve created the strawberry parts list,” said the consortium’s leader Kevin Folta, an associate professor with the University of Florida’s Institute of Food and Agricultural Sciences.
- For every organism on the planet, if you’re going to try to do any advanced science or use molecular-assisted breeding, a parts list is really helpful.
In the old days, we had to go out and figure out what the parts were. Now we know the components that make up the strawberry plant.” From a genetic standpoint, the woodland strawberry, formally known as Fragaria vesca, is similar to the cultivated strawberry but less complex, making it easier for scientists to study.
The 14-chromosome woodland strawberry has one of the smallest genomes of economically significant plants, but still contains approximately 240 million base pairs. The woodland strawberry is the smallest plant genome to be sequenced other than Arabidopsis thaliana, a small flowering plant in the mustard family, because it has only about 210 million base pairs, OSU plant molecular biologist Todd Mockler, one of the lead researchers, said.
Base pairs are the molecules known as adenine, cytosine, guanine and thymine that form a double-stranded DNA helix. As part of their findings, the scientists identified genes that they think might be responsible for some of the berry’s characteristics like flavor, aroma, nutritional value, flowering time and response to disease.
Knowing what individual genes do will allow researchers to breed crops for those specific traits. And in the case of tree fruits, they won’t have to wait years to see if those traits actually show up in the fruit. For example, with molecular breeding they would be able to cross a high-yielding pear tree with one that resists a certain fungal disease, and they’d be certain that the desired genes are actually present.
The consortium of 75 researchers from 38 institutions that sequenced the genome included two Georgia Tech researchers. They are Mark Borodovsky, a Regents professor with a joint appointment in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University and the Georgia Tech School of Computational Science and Engineering, and Paul Burns, who worked on the project as a bioinformatics Ph.D.
- Student. Once the consortium uncovered the genomic sequence of the woodland strawberry, Borodovsky and Burns led the efforts in identifying protein-coding genes in the sequence.
- Using a newly developed pattern recognition program called GeneMark.hmm-ES+, Borodovsky and Burns identified 34,809 genes, of which 55 percent were assigned to gene families.
The GeneMark.hmm-ES+ program iteratively identified the correct algorithm parameters from the DNA sequence and transcriptome data. The program used a probabilistic model called the Hidden Markov Model to pinpoint the boundaries between coding sequences – called exons – and non-coding sequences, which could be either introns or intergenic regions.
In identifying the genes, prediction and training steps were repeated, each time detecting a larger set of true coding and non-coding sequences used to further improve the model employed in statistical pattern recognition. When the new sequence breakdown coincided with the previous one, the researchers recorded their final set of predicted genes.
“GeneMark.hmm-ES+ is a hybrid program that uses both DNA and RNA sequences to predict protein-coding genes,” said Borodovsky, who is also director of Georgia Tech’s Center for Bioinformatics and Computational Genomics. “Our approach to gene prediction in the strawberry genome proved highly effective, with 90 percent of the genes predicted by the hybrid gene model supported by transcript-based evidence,” added Borodovsky.
Further analysis of the woodland strawberry genome revealed genes involved in key biological processes, such as flavor production, flowering and response to disease. Additional examination also revealed a core set of signal transduction elements shared between the strawberry and other plants. The woodland strawberry is a member of the Rosaceae family, which consists of more than 100 genera and 3,000 species.
This large family includes many economically important and popular fruit, nut, ornamental and woody crops, including the cultivated strawberry, almond, apple, peach, cherry, raspberry and rose. In the long term, breeders will be able to use the information to create plants that can be grown with less environmental impact, better nutritional profiles and larger yields.