Teacher guide
Squid ink and red hair get their color from the same family of pigments. Students watch Raven’s video on the three kinds of melanin, then work out how hair cells make black, blond, red or white hair. Pair this lesson with the evolution of skin color lesson.
At a glance
- Middle school
- Grades 6 to 8 · About 33 minutes
- High school
- Grades 9 to 12 · About 48 minutes
- College
- College · About 45 minutes
- Materials
- The worksheet for your level and a screen for the video.
- Grouping
- Students work alone. For partners, pair students for Questions.
- Phenomenon
- Squid ink, red hair, brown eyes and two dark patches deep in the human brainstem all get their color from one family of pigments, melanin.
- Topics
- Pigments, skin and hair color, tanning, UV damage and skin cancer, albinism, gray hair, Parkinson’s disease, squid ink, insect immunity. Around the 5-minute mark, Raven mentions pheomelanin in the lips and genital areas.
- Paired lesson
- The evolution of skin color lesson. This lesson covers what melanin is and how cells make melanin. The pair covers why human skin color varies around the world.
Preview the video before sharing it with your class.
Video and transcripts
- 1
The Science of Melanin Magic
8 minutes 21 seconds, posted September 7, 2020. Introduces eumelanin, pheomelanin and neuromelanin, then melanin in other living things, from squid ink to fungi.
Watch on YouTubeTranscript
From the English captions uploaded with the video.
Hi there. My name is Raven Baxter, also known as Raven the Science Maven. And let me tell you something. I think a lot of us have been walking around here saying melanin magic, melanin poppin’, melanin queen. But you don’t actually know the science behind what exactly melanin is. And I’m going to teach you guys today, don’t worry, you don’t have to be walking around here ignorant. No, I’m playing. (Raven chuckling) I’m sure that if you think that melanin is just something that gives your body its brown color, that you’re gonna learn something new today, and I’m gonna teach y’all, okay? All right.
Okay, I am a molecular biologist and science communicator and I am going to teach you about melanin today. The word melanin has a Greek root from melas and that means dark or black. And melanin itself is an umbrella term for pigments that are naturally occurring in organisms. What a lot of people don’t know about melanin is that there’s just not one type. Like when we say melanin magic, when we say melanin poppin’, we’re usually only talking about one type of melanin and that is the melanin that produces like brown and black pigments, and that’s eumelanin. But there’s two other types of melanin. There’s pheomelanin, which is largely responsible for producing red to yellow pigments. And then there’s also neuromelanin, which plays a different role in the body. I’m gonna talk about that later because that one is a little complicated. Let’s first talk about where melanin comes from, what it does and then I’m gonna get into like the specific types of melanin.
When human skin melanogenesis, which is a big word for creation of melanin, that is caused by or triggered by exposure to UV radiation. And where is the biggest source of UV radiation on this planet? It is from the sun. So our sun produces UV rays. It penetrates our atmosphere and it hits all of these surfaces on our planet, including human skin. When UV rays come into contact with human skin, our melanocytes, which are cells that produce melanin, start to make melanin. And that is why when we sit out in the sun for long periods of time, we get darker. We tan. Even I tan. Melanin is an effective absorbent of light. It actually is able to dissipate 99.9% of UV radiation. Because of this, we think that melanin might play a really big role in photo protection, protecting our skin cells, our melanocytes from DNA damage. UV light, if it hits our DNA, can cause damage to our DNA, which in turn can create cancer. So if our bodies are producing melanin, that means more protection potentially. We’re still trying to like understand that relationship between photo protection and skin pigmentation. But there’s good evidence out there that a deeper skin pigmentation could play a role in photo protection.
Melanin is not just found in the skin, it’s actually found in places like our hair. It’s found in our eyes even, in our brain stems and also even in our adrenal gland, which sits on top of our kidney. Isn’t that crazy? However, not all of us produce the same types of melanin or same levels of melanin. You may have heard of albinism or have seen someone who is albino, and that is someone that produces very little to no melanin. Therefore, their skin pigmentation is often very, very light, if not white.
Back to what I was saying earlier, there are three main types of melanin. Eumelanin, pheomelanin, and neuromelanin. Both pheomelanin and eumelanin are found in human skin and hair. But eumelanin is the most common type of pigment found in humans and in folks who have albinism, eumelanin is most likely the type of melanin that they are lacking. So let’s talk more about eumelanin. Eumelanin, which comes in two pigments, brown and black. Y’all have seen eumelanin in action in many different ways, not just in our skin, but even our hair. Remember I said melanin is not just found in our skin, it’s localized in other parts of our bodies. As we get older, our bodies stop producing as much brown eumelanin. And when that happens, our hair turns gray. A small amount of brown eumelanin in the absence of other pigments creates blonde hair. So if you can kind of think of melanin as an equation where there’s different colors or maybe even think about art where you have different colors and you’re putting colors in, you’re mixing colors together, taking away some colors, you get different pigments, you get different hues. I’m probably not using the correct art terms. Please forgive me. And if you’re a art person, correct me down in the comments. Y’all see what I’m saying? You get different shades, hues, pigments, colors. You get all of these different combinations. And that is the beauty of the diversity of the human spectrum of how we look. Varying shades of skin colors are all a reflection of the different amounts of the types of melanin that are produced in our bodies.
Pheomelanins are responsible for red to yellow pigmentation. Pheomelanin is most commonly concentrated in our lips. So inside of my lips are pink. I put pink lipstick on, but if you look in my mouth, my mouth is pink, and it’s also concentrated in our genital areas, okay? So I don’t even really wanna talk about that. But y’all got Google. Different parts of our bodies are also pink and that is because of pheomelanin. Let’s go back to the hair example. You have a small bit of brown eumelanin and a little bit of red pheomelanin, and together actually produces that orange-y red color or that ginger color as some people like to call it. Red heads, that’s what’s going on with y’all. Pheomelanin is also present in the skin, which is why usually when people have red hair, their skin is also a little bit pink as well. That’s the pheomelanin in action.
So we talked about eumelanin, which produces black to brown pigmentation. We talked about pheomelanin, which produces red to yellow pigmentation. Now we’re gonna get to the oddball and that is neuromelanin, which is produced in the brain. Scientists are still working to pin down what exactly the biological function of neuromelanin is. We know it’s a dark pigment. We know it’s produced in the brain. We also know that humans have the largest amount of neuromelanin and other primates have smaller amounts. It’s actually found to be totally absent in other species thus far. So that definitely says something but we’re not really sure. There are some studies going on linking it to Parkinson’s disease, which is really cool. I’ll link some of those studies down below. If you’re a fellow scientist and you wanna read into it, I welcome that. Welcome any cool discussions about any of this stuff, guys, it’s super interesting.
Let’s talk really quick about what melanin does for organisms that are not humans. Y’all ever seen a squid or octopus. Cephalopods in general squirt out ink, that dark stuff that squirts out when they are running away from predators, et cetera. That’s made up of mostly melanin. (Raven chuckling) Organisms of other species have also used melanin as a protective or defensive thing. Bacteria and fungi have also used melanin to protect themselves from UV radiation. In invertebrates, melanin actually plays a big role in their immune system in that when they have a pathogen that is coming into their bodies, they’ll actually coat the pathogen with melanin and kill it.
I talked a lot about melanin itself in this video but if you are interested in learning about how humans have evolved skin color over thousands of years and why I’m brown and somebody else is pink or white or why somebody else is more orange, et cetera and how those colors have developed over time, I want you to watch the next video that I’m coming out with. If it’s already out, then I’m gonna link it after this video. I’m gonna put the card up here and you guys can click on it and keep learning about the evolution of skin color over the past thousands of years. It’s really interesting, so don’t miss it. Let me know any of your questions down in the comments section below. I hope you enjoyed this and welcome to my channel, guys. I’m Raven the Science Maven. Keep being your unapologetic self. (lips popping) Bye. (lively music)
Your word of the day is
MEL-uh-nin
Melanin. A family of natural pigments that give color to skin, hair, eyes, feathers and more.
| Word part | Comes from | Meaning |
|---|---|---|
| melan- | Greek mélās | black |
| -in | New Latin -ina | an ending chemists use in names of compounds |
| eu- (bonus word) | Greek eú | well, good |
| pheo- (bonus word) | Greek phaiós | gray |
| neuro- (bonus word) | Greek neûron | nerve |
| -cyte (bonus word) | Greek kýtos | container, body, hollow vessel |
Same roots, other subjects
- History and artMelancholy, a gloomy state of mind, comes from Greek melancholía, “condition of having black bile.” In medieval thought, melancholy was one of four humors and was tied to black bile, also called black gall. Albrecht Dürer’s 1514 engraving Melencolia I takes its title from the same word.
- MathDürer’s Melencolia I includes a magic square. Each row and each column adds up to 34.
- BiologyA melanocyte is a cell that makes melanin. Melanoma, from melan- and -oma, is a skin cancer that grows from melanocytes.
- ChemistryChemists use -in in the names of many compounds, such as insulin, penicillin and aspirin. Keratin, the protein in hair and nails, has the same ending.
- MusicEuphony means a pleasing sound. Its eu-, “good,” is the same eu- in eumelanin.
- World languagesSpanish says melanina and French says mélanine.
Word hunt. Ask students to find three more words that start with melan- or end in -cyte and say what each word names.
Melanin joins melan-, “black,” to -in, a chemistry ending. Eumelanin, pheomelanin and neuromelanin each put a prefix in front of melanin. A melanocyte, from melano- and -cyte, is a cell that makes melanin. The worksheets carry a short version. Use these for discussion or a word hunt.
Lesson flow
- 3 minPredictStudents answer the question and write one sentence.
- About 9 minVideoPlay the video from start to finish.
- 4 minWord of the dayBreak the word into its parts together.
- 8 minQuestionsStudents answer on their own, then share out. With partners, pairs discuss first.
- 5 minExit ticket
- 3 minPredictStudents answer the question and write one sentence.
- About 9 minVideoPlay the video from start to finish.
- 4 minWord of the dayBreak the word into its parts together.
- 8 minQuestionsStudents answer on their own, then share out. With partners, pairs discuss first.
- About 10 minClaim, evidence, reasoning
- About 5 minGoing further
- 5 minExit ticket
- About 9 minVideoPlay the video from start to finish.
- 4 minWord of the dayBreak the word into its parts together.
- 3 minPredict
- About 20 minRead the paperStudents read Table 2 of the paper and answer the questions. The paper reading works as homework or a discussion section.
- 5 minExit ticket
Video simplifications
- 99.9% of UV
- The video says melanin can “dissipate 99.9% of UV radiation.” Meredith and Riesz found eumelanin turns more than 99.9% of the UV and visible energy it absorbs into heat. Brenner and Hearing estimate skin melanin absorbs about 50 to 75% of UV, close to an SPF of 1.5 to 4. The high school Going further question works through the difference.
- Melanin and UV
- The video says melanin forms when UV hits skin. UV triggers extra melanin, the tan. Skin also holds a baseline level of melanin set by genes, called constitutive pigmentation.
- Gray hair
- The video says hair turns gray when the body stops making as much brown eumelanin. In a study of graying hair, hair bulbs lost their melanocytes, and white hair bulbs held no detectable melanocytes. With no melanocytes, the hair gets no melanin of either kind.
- Pink lips
- The video says pheomelanin concentrates in the lips and genital areas and makes pink body parts pink. No source opened for this lesson supports that claim. Skin color comes from carotenoids and from oxygenated and deoxygenated hemoglobin in blood as well as from melanin.
- Red hair and pink skin
- The video says red-haired people’s skin looks pink because of pheomelanin. Weakly working MC1R, common in red-haired people, lowers eumelanin and goes with fair skin.
- Albinism
- The video says people with albinism most likely lack eumelanin. OCA1A, the most severe type, makes no melanin of either kind. Milder types make some pigment over time.
- Neuromelanin in other animals
- The video says neuromelanin is “totally absent in other species thus far,” with humans highest and other primates lower. The sources opened confirm that mice and rats make none. They don’t rank species.
- Adrenal gland
- The video says melanin occurs in the adrenal gland. No source opened for this lesson confirms the claim.
- Squid ink
- The video says cephalopod ink is “made up of mostly melanin.” Melanin gives the ink its black color and makes up about 15% of the wet weight of cuttlefish ink. Proteins add another 5 to 8%.
- Bacteria and fungi
- The video says bacteria and fungi use melanin against UV. A review confirms the protective role in fungi, where melanized yeasts resist radiation better than albino yeasts. Bacteria were not checked for this lesson.
- Invertebrate immunity
- The video’s line checks out for insects. Melanin forms around invading microbes and parasites and helps kill the invaders.
- Pronunciation
- Melanin is MEL-uh-nin. Eumelanin is yoo-MEL-uh-nin. Pheomelanin is fee-oh-MEL-uh-nin. Neuromelanin is noor-oh-MEL-uh-nin.
Worksheet
Predict
Squids squirt a cloud of dark ink when a predator comes close. Your hair gets its color from a pigment called melanin. Could squid ink and your hair get their color from the same kind of pigment?
Circle one. Yes / No
Watch
- The Science of Melanin Magicyoutube.com/watch?v=5Dt1NYLqMqM
Word of the day
Melanin (MEL-uh-nin). A family of natural pigments that give color to skin, hair, eyes, feathers and more.
| Word part | Comes from | Meaning |
|---|---|---|
| melan- | Greek mélās | black |
| -in | New Latin -ina | an ending for names of chemicals |
- Melancholy, a word for deep sadness, comes from Greek words meaning “black bile.”
- Keratin, the protein that makes up your hair, ends in -in too.
Bonus word. Melanocyte (muh-LAN-uh-site). Melano- means “black,” and -cyte means “cell.” A melanocyte is a cell that makes melanin.
Questions
Melanin comes in three main kinds. Eumelanin makes brown and black colors. Pheomelanin makes red and yellow colors. Neuromelanin is found in the brain. Which kind of melanin gives red hair its red color?
Circle one. Eumelanin / Pheomelanin / Neuromelanin
Hint. Look for the kind of melanin that makes red and yellow colors.
Melanocytes are the cells that make melanin in your skin. Each melanocyte passes melanin to about 36 skin cells nearby. Inside those skin cells, the melanin collects in a cap over the part of the cell that holds the DNA. How does melanin from one melanocyte help protect the skin cells nearby from the sun?
Hint. UV rays from the sun can damage DNA. What does the melanin cap sit on top of?
People with light skin and people with dark skin have about the same number of melanocytes. Light skin and dark skin have about the same number of melanocytes. What makes one person’s skin darker than another person’s?
Hint. Think about what the melanocytes make, not how many melanocytes there are.
Squids, octopuses and cuttlefish squirt ink when a predator attacks. The ink gets its dark color from melanin. How could a dark cloud of ink help a squid escape from a predator?
Hint. Think about what the predator can see after the ink spreads through the water.
Exit ticket
Hair color comes from melanin made by melanocytes. How can the same kind of cell make black hair, blond hair or red hair?
Hint. Think about the kind of melanin and the amount of melanin.
Predict
Squids squirt a cloud of dark ink when a predator comes close. Your hair gets its color from a pigment called melanin. Could squid ink and your hair get their color from the same kind of pigment?
Circle one. Yes / No
Watch
- The Science of Melanin Magicyoutube.com/watch?v=5Dt1NYLqMqM
Word of the day
Melanin (MEL-uh-nin). A family of natural pigments that give color to skin, hair, eyes, feathers and more.
| Word part | Comes from | Meaning |
|---|---|---|
| melan- | Greek mélās | black |
| -in | New Latin -ina | an ending chemists use in names of compounds |
- Melancholy, a word for deep sadness, comes from Greek melancholía, “condition of having black bile.”
- Keratin, the protein that makes up hair and nails, carries the same -in ending as melanin.
Bonus words from the video. Eumelanin (yoo-MEL-uh-nin) adds eu-, “good,” and names the brown to black melanin. Pheomelanin (fee-oh-MEL-uh-nin) adds pheo-, from the Greek word for “gray,” and names the red to yellow melanin. Neuromelanin (noor-oh-MEL-uh-nin) adds neuro-, “nerve,” and names the dark melanin in the brain.
Questions
The enzyme tyrosinase turns the amino acid tyrosine into dopaquinone. When the amino acid cysteine is present, cysteine joins dopaquinone, and the pathway makes pheomelanin. When cysteine runs out, the pathway makes eumelanin. Tyrosine’s formula is C9H11NO3, and cysteine’s formula is C3H7NO2S. Pheomelanin contains sulfur, and eumelanin doesn’t. Where do the sulfur atoms in pheomelanin come from?
Hint. Atoms don’t appear out of nowhere in a chemical reaction. Find the S in the two formulas.
In lab experiments, scientists gave pigment cells small pieces of DNA that mimic UV damage. The cells made about 7 times more melanin. Painted on guinea pig skin, the same DNA pieces produced a visible tan. What do the DNA experiments suggest about the signal that tells melanocytes to make a tan?
Hint. The DNA pieces copied damage, not sunlight. What could the melanocytes be responding to?
Neuromelanin collects with age in two areas of the human brainstem. In Parkinson’s disease, the brain loses many of the neurons that hold the most neuromelanin. Mice and rats, the most common lab animals, make no neuromelanin. Why does the lack of neuromelanin in mice and rats make Parkinson’s disease harder to study in those animals?
Hint. A lab animal stands in for a human brain. What would a mouse brain be missing?
Melanin makes up about 15% of the weight of cuttlefish ink, and proteins add another 5 to 8%. Some squid release ink as a loose cloud. Others release a blob of ink and mucus that looks like a squid. How could a squid-like blob of dark ink help a squid escape? And why does melanin’s dark color help the ink work?
Hint. Think about where a predator aims an attack.
Claim, evidence, reasoning
Albinism type OCA1A comes from changes in the tyrosinase gene, TYR. People with OCA1A make no melanin from birth onward, and their hair is white. How can a change in one gene, TYR, remove both eumelanin and pheomelanin from hair, skin and eyes? Make a claim, back the claim with evidence and explain your reasoning.
Hint. Look back at the tyrosinase reaction in Questions 1. Which enzyme does each kind of melanin need first?
Going further: UV and heat
A 2004 physics study found that eumelanin turns more than 99.9% of the UV and visible light energy it absorbs into heat. A 2008 review estimated that melanin in skin works like a sunscreen of about SPF 1.5 to 4, absorbing about 50 to 75% of UV rays. Someone reads the 2004 study and says melanin blocks 99.9% of the UV rays that hit skin. Is the claim that melanin blocks 99.9% of the UV rays hitting skin valid? Use both numbers to back up your answer.
Hint. Compare “the UV that reaches skin” with “the UV energy melanin has already absorbed.” What happens to light energy after matter absorbs the light?
Exit ticket
Eumelanin and pheomelanin share their first steps. The MC1R signal tells a melanocyte which kind to make, and a strong signal leads to eumelanin. How do tyrosinase, MC1R and cysteine work together to determine whether a melanocyte makes eumelanin, pheomelanin or no melanin?
Hint. Put tyrosinase, MC1R and cysteine in the order the cell uses them.
Watch
- The Science of Melanin Magicyoutube.com/watch?v=5Dt1NYLqMqM
Word of the day
Melanin (MEL-uh-nin). A family of pigments in living things. Cells make eumelanin and pheomelanin from the amino acid tyrosine.
| Word part | Comes from | Meaning |
|---|---|---|
| melan- | Greek mélās | black |
| -in | New Latin -ina | an ending chemists use in names of compounds |
- Melancholy, a word for deep sadness, comes from Greek melancholía, “condition of having black bile.”
- Keratin, the protein that makes up hair and nails, carries the same -in ending as melanin.
Bonus words. Eumelanin (yoo-MEL-uh-nin, from eu-, “good”) names the brown to black melanin. Pheomelanin (fee-oh-MEL-uh-nin, from pheo-, “gray”) names the red to yellow melanin, which contains sulfur.
Predict
Red hair holds a lot of pheomelanin. Chemists track pheomelanin with TTCA, a marker molecule that comes from pheomelanin when hair is broken down. Before you read the paper, take a guess. Black hair holds what percent of red hair’s TTCA? Give your reason in one sentence.
Hint. Think about which kind of melanin the video says colors black hair.
Read the paper
Ito and others, “Improved HPLC Conditions to Determine Eumelanin and Pheomelanin Contents in Biological Samples Using an Ion Pair Reagent,” International Journal of Molecular Sciences, 2020. The paper is free to read.
Chemists measure melanin by breaking the pigment into small marker molecules and measuring the markers. Alkaline hydrogen peroxide breaks eumelanin into PTCA, PDCA and PTeCA, and breaks pheomelanin into TTCA and TDCA. The markers show how much of each melanin a sample holds and what its building blocks look like. Table 2 of the paper reports all five markers in one sample of black human hair and one sample of red human hair, from five repeat analyses. Values are means ± standard deviation, in nanograms of marker per milligram of hair. The coefficient of variation (CV) sits in parentheses. PTCA, PDCA and PTeCA come from eumelanin. TTCA and TDCA come from pheomelanin.
| Hair | PTCA | PDCA | PTeCA | TTCA | TDCA | TTCA ÷ PTCA |
|---|---|---|---|---|---|---|
| Black | 205 ± 4.4 (2.1%) | 19.2 ± 0.60 (3.2%) | 82.0 ± 3.6 (4.4%) | 43.4 ± 0.94 (2.2%) | 19.4 ± 1.9 (9.7%) | |
| Red | 23.4 ± 1.2 (5.2%) | 10.7 ± 0.52 (4.8%) | 12.9 ± 1.6 (12.4%) | 169 ± 6.7 (4.0%) | 26.7 ± 0.86 (3.2%) |
For each hair color, fill in the last column of the table by dividing TTCA by PTCA. How many times higher is red hair’s TTCA-to-PTCA ratio than black hair’s ratio? And what percent of red hair’s TTCA does black hair hold?
Hint. Find both ratios first. For the percent, divide black hair’s TTCA by red hair’s TTCA.
TTCA and TDCA are thiazoles, rings that hold a sulfur atom (thiazole is C3H3NS). PTCA, PDCA and PTeCA are pyrroles, rings with no sulfur (pyrrole is C4H5N). Pheomelanin forms when the amino acid cysteine (C3H7NO2S) joins dopaquinone, which tyrosinase makes from tyrosine (C9H11NO3). Black hair yielded 43.4 nanograms of TTCA per milligram. What does that TTCA tell you about cysteine inside the melanocytes that colored black hair?
Hint. Trace the sulfur atom. Which starting molecule could have supplied the sulfur?
Table 2 gives each value as mean ± standard deviation from five repeat analyses, with the CV in parentheses. Most CVs fall under 5%, but PTeCA in red hair reached 12.4% and TDCA in black hair reached 9.7%. Why would PTeCA in red hair and TDCA in black hair vary more than the other markers? And why run the same hair sample five times?
Hint. Look at how much of each marker the hair holds. Then look at Table 1 of the paper, where a smaller slope means a smaller detector signal for the same amount of marker.
Eumelanin absorbs UV and soaks up harmful oxidants. Pheomelanin blocks less UV and can produce reactive oxygen species when UV hits the pigment. People whose MC1R works weakly often have red hair and fair skin. Based on Table 2, which would likely give skin less protection from UV, melanocytes like the red-hair ones or the black-hair ones? And what would you measure in skin to test that prediction?
Hint. Hair isn’t skin. Think about which samples and which kind of damage you would measure.
Exit ticket
Table 2 compares five melanin markers in one black hair sample and one red hair sample. What does Table 2 show? And what’s one question Table 2 can’t answer?
Hint. Start with your ratios. Then think about what two hair samples and a set of marker numbers leave out.
Standards
The lesson builds toward three Next Generation Science Standards (NGSS), the most widely used US science standards. Some states, like Texas and Virginia, write their own. NGSS covers kindergarten through grade 12. The college worksheet uses the AAAS Vision and Change framework for undergraduate biology. MS-LS1-3 assesses six body systems, and skin is not among the six. Questions 2 uses skin cells to teach the standard’s core idea.
| Level | Standard | Lesson part | Practice | Crosscutting concept |
|---|---|---|---|---|
| Middle school | MS-LS1-3. Argue from evidence that the body is a system of interacting subsystems made of groups of cells (core idea LS1.A) | Middle and high school worksheets, Questions 2 | Engaging in Argument from Evidence | Systems and System Models |
| High school | HS-LS1-1. Explain how the structure of DNA sets the structure of proteins that carry out life’s work in specialized cells (core idea LS1.A) | High school worksheet, claim, evidence, reasoning | Constructing Explanations and Designing Solutions | Structure and Function |
| High school | HS-PS4-4. Evaluate published claims about what electromagnetic radiation does when matter absorbs the radiation (core idea PS4.B) | High school worksheet, Going further | Obtaining, Evaluating, and Communicating Information | Cause and Effect |
| College | AAAS Vision and Change. Core concepts: structure and function; pathways and transformations of energy and matter | College worksheet | Core competencies: quantitative reasoning; process of science; interdisciplinary nature of science | Core concept: structure and function |
Sources
The lesson draws on several research teams and credits each team.
| Topic | Who found it | Where it was published |
|---|---|---|
| Melanin markers in black and red hair, Table 2 of the college worksheet | Shosuke Ito, Sandra Del Bino, Tomohisa Hirobe and Kazumasa Wakamatsu, at Fujita Health University, L’Oréal Research and Innovation and Shinjuku Skin Clinic | International Journal of Molecular Sciences, 2020 |
| Hair color from the amount and mix of eumelanin and pheomelanin | Shosuke Ito and Kazumasa Wakamatsu, Fujita Health University | Journal of the European Academy of Dermatology and Venereology, 2011 |
| Melanin and UV protection, melanocyte numbers, tanning | Michaela Brenner and Vincent Hearing, National Cancer Institute | Photochemistry and Photobiology, 2008 |
| Eumelanin turns more than 99.9% of absorbed light energy into heat | Meredith and Riesz, University of Queensland | Photochemistry and Photobiology, 2004 |
| MC1R and the switch between eumelanin and pheomelanin | Erin Wolf Horrell, Mary Boulanger and John D’Orazio, University of Kentucky | Frontiers in Genetics, 2016 |
| Albinism and the tyrosinase gene | Karen Grønskov, Jakob Ek and Karen Brondum-Nielsen, Kennedy Center, Denmark | Orphanet Journal of Rare Diseases, 2007 |
| How cysteine steers dopaquinone toward pheomelanin, and the same eumelanin to pheomelanin mix in skin from very light to dark | Sandra Del Bino, Shosuke Ito, Juliette Sok and Kazumasa Wakamatsu, at L’Oréal Research and Innovation and Fujita Health University | Pigment Cell and Melanoma Research, 2022 |
| Gray hair and the loss of hair follicle melanocytes | Commo, Gaillard and Bernard, L’Oréal Recherche | British Journal of Dermatology, 2004 |
| Neuromelanin builds up with age in the brainstem | Luigi Zecca and colleagues | PNAS, 2004 |
| Neuromelanin, Parkinson’s disease and animal models | Svenja Esser, Maximilian Hausherr and colleagues, Ruhr University Bochum | Biomedicines, 2025 |
| Cephalopod ink | Charles Derby, Georgia State University | Marine Drugs, 2014 |
| Fungal melanin and radiation | Radames Cordero and Arturo Casadevall, Johns Hopkins Bloomberg School of Public Health | Fungal Biology Reviews, 2017 |
| Melanin in insect immunity | Agnieszka Zdybicka-Barabas, Sylwia Stączek, Magdalena Kunat-Budzyńska and colleagues, Maria Curie-Skłodowska University | International Journal of Molecular Sciences, 2025 |
The 2011 hair paper, the 2004 gray hair paper and the 2004 Meredith and Riesz paper sit behind a paywall, and their PubMed abstracts are free. The rest are free to read.
- Research papers, linked in the table above
- Vision and Change core concepts and competencies, as summarized in Brownell and others, CBE Life Sciences Education, 2014
- Word origins and formulas from Dictionary.com: melanin, melano-, -in, eumelanin, pheomelanin, neuromelanin, melanocyte, -cyte, eu-, neuro-, melancholy, melanoma, keratin, euphony, tyrosine, cysteine, pyrrole, thiazole
- The Metropolitan Museum of Art, “A Happy Occasion for Melencolia I”
- Spanish and French spellings from Wiktionary
- Transcript from the English captions uploaded with the YouTube video
- NGSS MS-LS1-3, HS-LS1-1, HS-PS4-4