Hagfish and Lampreys

The Eye Takes a Big StepChuck Schobert, DVM

Comparison

The Chordates in Evolution

Hagfish and Lampreys• No paired pectoral (shoulder) or pelvic (hip) fins• Notochord persists for life.• They have no scales.• The axons of their neurons are unmyelinated.• Lampreys have both an innate immune system

and an adaptive immune system, but the latter is entirely different from that found in the jawed vertebrates.

Hagfish• Eat dead whales• Secrete copious

amounts of thick slime (mucous)

• Live in deep oceanic trenches (>100meters)

• Recommendation: YouTube: “Eddie and the Hagfish”

Hagfish Eyes

• No cornea• No lens• 2-layered retina (cellular)• No melanin• Primitive photoreceptors• Wired to the brain like a

pineal gland• No pineal gland• Photoreceptors synapse

directly onto ganglion cells

Eye

Hagfish Specimen courtesy of Dr Ivan Schwab

Lamprey Eye: Larval

• Larval form to adult form: Five Years!

• Mostly buried in mud • No lens initially

• Larva details– Similar to hagfish eye– Eye covered in skin

Lamprey Larval Eye

Lamprey Adult•Cornea largely continuous with the skin•No muscles of accommodation•Has most of the structures of the vertebrate eye:

–Lens–3-layered retina–Extraocularmuscles–Wired to brain like a visual eye–Melanin in choroid and RPE

Color vision and pineal gland

Lamprey Adult Eye: Five Years Later

Photoreceptor Evolution

From Lamb, TD et al. Evolution of the Vertebrate eye: opsins, photoreceptors, retina and eye cup. 2007. Nature Reviews: Neuroscience, 8: 960-975.

Hagfish Lamprey

Take Home?• A window to the earliest development of the

vertebrate eye– Hagfish: circadian function– Lamprey: image-forming eye, vertebrate-like– Evolutionary controversy about relationship between

hagfish and lamprey: – If hagfish is basil to chordates, opportunity to see the

earliest examples of vertebrate ocular evolution– If hagfish is closer to the lamprey (clade) then ocular

differences are perhaps degenerate• And of course, weird food

Hagfish-Slime Cheddar-Gruyere Scones

4 cups all-purpose flour2 tablespoons baking powder4 teaspoons sugar1/2 teaspoon salt1 cup (two sticks) chilled unsalted butter, cut into 1/2-inch cubes2 cups (packed) coarsely grated extra-sharp yellow cheddar cheese (about 9 ounces), or a mix of 6 ounces cheddar and 3 ounces gruyere.1-1/2 cups chilled heavy whipping cream6 tablespoons hagfish slimePreheat oven to 375F

In a food processor, blend flour, baking powder, sugar, and salt. Cut in the butter using quick pulses until the mixture resembles coarse meal. Add cheese and cut in using quick pulses. In a small bowl, whisk together the cream and hagfish slime. With the food processor running, add cream mixture through feed tube. Process until dough just holds together – don’t overmix!

Turn dough out onto a lightly floured work surface. Gather the dough together and divide into quarters. Pat each quarter into a round just short of 1 inch high (it should be about 6-7 inches in diameter). Using a clean, sharp knife, cut each round into six wedges. Transfer half the wedges to ungreased baking sheets lined with parchment paper, spacing them about 2 inches apart.

Bake the first batch of scones until the edges just start to brown and a toothpick comes out clean, about 20 minutes. Transfer them, still on their parchment paper, to a wire rack to cool at least 10 minutes, during which time put in the second batch of scones.

Serve warm or at room temperature. The scones will stand for about 8 hours. Do not refrigerate. If you want to reheat them, warm them in a 350F oven for about 5 minutes

Lamprey BordelaiseFor : 6 servingsTime : 2 h 50Difficulty : medium

Ingredients for Lamprey Bordelaise :• 1 live 2 kg lamprey • 1 dl oil • 100 g butter • 1 bottle red Bordeaux wine • 1 small glass Armagnac • 4 shallots • 8 onions • 15 leeks• 4 garlic cloves • 600 g Bayonne ham • 2 tablespoons flour • 1 glass broth • 2 cloves • 1 bouquet garni• 6 slices country-style bread • salt • Pepper

Technical stages for Lamprey Bordelaise :

• Bleed the lamprey by hanging it by the head and cutting the tail over a container to collect the blood. When there's no blood dripping anymore, dip the lamprey in boiling water for 1 minute.

• Take it out and peel it. Cut in 4 cm-thick (1,57 inches) slices. Put the slices in the container of blood. • Cut the white part of the leeks into 7-8 cm-long (2,76-3,15 inches) whistles and steam them in butter. • Add the diced ham, the shallots and minced onions. Sprinkle with flour and roast. • Moisten with the wine and broth. Add the cloves and bouquet garni. Add pepper, salt a little. Add two crushed garlic cloves. Bring to a boiling point, then cook for 45

minutes over low heat. • 45 minutes later, add the pieces of lamprey in the sauce, cover and cook again for 45 minutes. • Remove the slices of fish, and flamb them in another pan or skillet with Armagnac. • Pour the equivalent of a glass of warm sauce over the blood in order to dilute it, and poor in the skillet. Stir well. Put back the lamprey, season and cook for 10 minutes

with the lid on. Beat the sauce with butter. • Meanwhile, toast the bread and rub it with the remaining garlic.Put the lamprey in a shallow dish, on the slices of bread. Put the leeks all around. Coat with the sauce.

Thanks to:

• Dr Dick Dubielzig• Dr Ivan Schwab• Ms Janice Lokken

Questions or Comments?