Homework assignment:

All classes: Write a 1-page paper about your dragon.  How
do your dragon's traits help your dragon survive in its environment?

4th Period: Sea Slug Current Event due any time between now and Friday, Feb. 20, 2015.  The unedited article is at:

http://www.sciencedaily.com/releases/2015/02/150203155925.htm

I've also inserted a copy of the current event to the blog if you don't have yours.

Sea Slug Has Taken Genes From Algae It Eats, Allowing It To Photosynthesize Like A Plant
Author: Diana Kenney, Marine Biological Laboratory   Date: February 3, 2015 
[Edited for reading level by Mr. Goldsmith]

A …green sea slug can live for months at a time "feeding" on sunlight, like a plant[, says] a recent study …in The Biological Bulletin.

The authors present the first direct evidence that the emerald green sea slug's chromosomes have some genes that come from the algae it eats.

These genes help sustain photosynthetic processes inside the slug that provide it with all the food it needs.

Importantly, this is one of the only known examples of [transfers of a gene that is then used by the second species] from one multi-cellular species to another.  [Some scientists are researching this in] gene therapy to correct genetic… diseases in humans.

"Is a sea slug a good [biological model] for a human therapy? Probably not. But figuring out the mechanism of this natural…gene transfer could [teach us a lot] for future medical [use]," says study co-author Sidney K. Pierce, … professor at universities in Florida and Maryland.

The team used an advanced imaging technique to confirm that a gene from an algae (V. litorea) is present on the chromosome of the slug (E. chlorotica). This gene makes an enzyme … critical to the function of photosynthetic "machines" called chloroplasts, typically found [only] in plants and algae.

It has been known since the 1970s that [the sea slug] "steals" chloroplasts and embeds them into its own digestive cells. [Stealing genes from the algae is called "kleptoplasty".]  Once inside the slug cells, the chloroplasts continue to photosynthesize for up to nine months. [This is] much longer than [chloroplasts] would perform in the algae. The photosynthesis process produces carbohydrates and [fats], which nourish the slug.

How [does] the slug [keep using] these photosynthesizing organelles for so long? [Scientists have intensely studied and argued about this].  "[An] algae gene needed to repair damage to chloroplasts, and keep them functioning, is … on the slug chromosome," Pierce says. "The gene is incorporated into the slug chromosome and transmitted to the next generation of slugs." While the next generation must take up chloroplasts anew from algae, the genes to maintain the chloroplasts are already present in the slug genome, Pierce says.

"There is no way on earth that genes from an algae should work in an animal cell," Pierce says. "And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they [won’t starve] to death until they find more algae to eat. "

This … adaptation is also [part] of rapid evolution, Pierce says. "When a successful transfer of genes between species occurs, evolution can basically happen from one generation to the next," he notes, rather than over [the usual] time scale of thousands of years.

Name_______________________  date _____________ Per._____________

Answer the following:

1.      Give credit (Cite T.A.D.S.).   Write the information out below, or get a zero.

Title:_________________________________________Author_________________ 

Date: ______________   Source:_______________________________   

• Answer all of the questions below in complete, written sentences, and
•  be sure to cite evidence from the article,
•  or get a zero.

2. Main Idea: What surprising ability has appeared in sea slugs?

3. Supporting Details: Why is this ability surprising?

4. Supporting Details: How did sea slugs get this ability? What parts (organelles) do sea slugs need to get and wheere do they get them from?

5. Supporting Details: What is unusual about how sea slugs are able to use chlorplasts?

6. Supporting Details: Why is this information important to people?

7. Vocabulary: what is an enzyme?  (Look it up).