Cellular Division of Coleonyx variegatus

1. Cellular Division of Coleonyxvariegatus By nico Gonzalez, eddiemckee, and griffin brownback

2. Biological Taxonomy (Kingdom) • C. variegatus(The Western Banded Gecko) belongs to the Animalia kingdom • Characteristics of Animalia: • Multicellular • Eukaryotic • In contrast to prokaryotic cells which, most prominently, contain no membrane-bound organelles and have DNA floating freely within their cytoplasm • Heterotrophic • Have a sexual development cycle that involves motile sperm • Utilize extracellular collagen as skeletal material

3. Biological Taxonomy (Genus) • The gecko is a member of the Coleonyx genus which hails from the Gekkonidae family • Characteristics of the Coleonyxtaxonomic rank: • Terrestrial geckos • Found throughout southwestern United States and Mexico • Relatively small lizards • Generally around five to six inches in length • Nocturnal • Inhabit dry and rocky habitats

4. Biological Taxonomy (Species) • The Western Banded Gecko’s species is classified as C. variegatus • Characteristics of C. variegatus • Prevalent in southwestern United States and northern Mexico • Range in length from four to six inches • Hatchlings measure around one inch • Sandy-colored bodies with reddish-brown bands • Scales produce a silky texture • Unlike other geckos, they have movable eyelids • Slender toes • Does not have toe pads

5. Cellular Division - Mitosis • Mitosis is a four-step cellular division process by which a single cell separates the chromosomes within its nucleus to create an identical daughter cell. • Process: • Stage One: Prophase • Chromatin coils and condenses to form compact chromosomes • Nuclear envelope begins to dissolve, exposing the nucleus • Organelles called centrosomes begin to shift to opposite sides of the nucleus • Protein strands emanating from the centrosomes begin to attach to the chromosome • These spindle fibers, or microtubules, attach to structures in the chromosomes’ centromeres called kinetochores

6. Cellular Division, cont. • Stage Two: Metaphase • Centromeres in the chromosomes are aligned along the cell’s equator by the microtubules • Chromosomes are now prepared for division • Stage Three: Anaphase • Microtubules on either side of the chromosome begin to shorten, applying oppositely directed pressures on the centromere • Sister chromatids split from the pressure, thus creating two chromosomes • Chromosomes gradually move towards the cell’s poles • Chromosomes are now ready to enter the final phase of mitosis

7. Cellular Division, cont. • Part Four: Telophase • The chromosomes reach their poles • Spindle fibers begin to disintegrate • Nuclear envelopes are reconstructed around both chromosome bundles • Chromosomes progressively unwind to become chromatin, once again • Cytokinesis • Not officially a part of mitosis, yet it concludes the process • Cytoplasm within the nucleus begins to separate • Eventually, the cytoplasm splits and forms two identically similar cells • The cell has officially multiplied/divided

8. Role of Mitosis in C. variegatus • Limb regeneration evolved as a self defense mechanism • Geckos are capable of detaching their tails when faced with a predator in order to create a diversion • This is made possible due to a significant weakness in the integrity of muscle tissue within the tail • Once detached, the blood vessels contract, preventing death due to blood loss • Although death has been (hopefully) evaded, the geckos still suffer from their escape • Many crucial nutrients and proteins once stored in the tail are now gone, causing the gecko to use a noticeably larger amount of energy to acquire food to supplement its tail regeneration • Mitosis • Once the tail is detached, the body immediately goes into recovery mode and begins the process of mitosis • Cells begin to multiply in order to recreate the tail and restore proper function to the gecko • After about two months of nonstop division, the cells near and in the geckos tail begin to abate their multiplication and regenerate at a slower rate since the tail is now replaced

9. Importance • Benefits of Understanding Cell Division: • Greater understanding leads to safer medical practices • Knowing how biological systems work helps us to understand our nature • Cell division provides a fundamental explanation of how organisms strive, grow, and reproduce • Understanding an organism’s biology is the first step to giving it proper treatment • Injured animal or human

10. Application • Studying biological processes can give medical insights on how to treat injuries • Can help doctors develop new treatments to aid in the recovery of spinal cord damage • If a sports player were to injure his spine, causing immobility, doctors could perhaps apply the knowledge gained from studying cell division into therapy • Knowing that the nervous system relies on a network of nerves to communicate with the body, the doctors could reach the conclusion that the once-paralyzed section of the body can be repaired • To restore movement to the body, the doctors would have to restore the severed nerves by synthesizing new ones • This restoration can be accomplished through stem cells, which ‘turn into’ the cells surrounding it, and multiply as if it were a cell of that certain tissue • In turn, this stem cell has the potential to repopulate the nerve cells and ultimately restore the nervous system to its prior self

11. References Abildgaard, M. (2008, January 7). 080106193147 [Illustration]. Retrieved from http://www.sciencedaily.com/releases/2008/01/080106193147.htm Brennan, T. C. (2008). Western banded gecko coleonyxvariegatus. Retrieved from http://www.reptilesofaz.org/Lizards-Subpages/h-c-variegatus.html Coleonyx. (2013, February 26). Retrieved from https://en.wikipedia.org/wiki/Coleonyx Coleonyxvariegatus [Photograph]. (2012). Retrieved from https://upload.wikimedia.org/wikipedia/commons/2/23/Coleonyx_Variegatus.jpg Description of animalia. (2008, December 10). Retrieved from http://eol.org/data_objects/15559532 DNA_Image [Painting]. (2013). Retrieved from http://blog.dataprotection.com/bid/62857/Is-DNA-a-Viable-Data-Storage-Method-for-the-Future How do lizards' tails grow back? (2012, June 23). Retrieved from http://brittanytodd.hubpages.com/hub/Why-do-Lizards-Lose-their-Tails-Limb-Regeneration Major events in mitosis [Photograph]. (n.d.). Retrieved from https://commons.wikimedia.org/wiki/File:Major_events_in_mitosis.svg Mitosis[Image]. (n.d.). Retrieved from http://recursostic.educacion.es/ciencias/biosfera/web/alumno/4ESO/seruni-pluricelulares/contenidos8.htm Mitosis. (2010). Retrieved from http://www.sumanasinc.com/webcontent/animations/content/mitosis.html Mitosis [Video file]. (2011, August 4). Retrieved from http://youtu.be/C6hn3sA0ip0 Nucleus_1 [Photograph]. (n.d.). Retrieved from http://nursingcrib.com/anatomy-and-physiology/anatomy-and-physiology-cells/ Prival, D. (2013). Western_banded_gecko [Photograph]. Purves, D. (2010). Figure 8 [Photograph]. Retrieved from http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookdivers_class.html Taxonomy [Photograph]. (2010). Retrieved from http://www.doddhollow.com/biology/lab14.php