Pitx1 is a gene with in a larger family of similar genes, referred to as homeobox genes that direct the formation of many body structures during early embryonic development. Pitx1 in particular, encodes for a protein of some 283 amino acids (varying slightly in different species) that acts as a transcription factor and is in charge of regulating the expression of other genes involved in the differentiation and function of certain developmental regions. The scientists in this study have been interested in the role of this Pitx1 protein and the differentiation and function of the development in particular of the hind limb regions in the threespin stickleback fish. Through their previously conducted studies these scientists concluded that the …show more content…
In order to test the hypothesis and ensure that other genes in the larger chromosome region were not the real cause of pelvic loss the scientists generated F1 hybrids between both pelvic-completed and pelvic-reduced sticklebacks as well as two pelvic-complete populations. These F1 hybrids allowed for combination of the alleles of Pitx1 from pelvic-complete (FRIL, LITC) and pelvic-reduced (PAXB) populations. Brain and pelvic tissues were isolated to compare the expression of either the LITC or PAXB allele to the FRIL allele. The results supported the initial hypothesis as expression of the PAXB Pitx1 allele was greatly reduced in the pelvis but not the head of F1 hybrids, indicating a tissue-specific, cis-regulatory change in the Pitx1 locus. If indeed other genes in the larger chromosome region were the real cause of pelvic reduction then there would have been a secondary or trans-acting reduction seen in the expressions of Pitx1 in both …show more content…
EGFP is a powerful reporter molecule for monitoring gene expression, protein localization and protein-point interaction. Through the use of EGFP, the scientists were able to see what areas of embryonic development this intergenic region of the Pitx1 was correlated with. Therefore, EGFP will be visibly expressed in areas within the intergenic region of the Pitx1 gene as well as within any of the developing embryonic regions that it is correlated with. Seeing that the only region where EGFP was consistently expressed was in the hindfin area, the scientists concluded that the non-coding region upstream of Pitx1 contained a tissue-specific enhancer for hindfin expression. Again, supporting their hypothesis that indeed Pitx1, and no other genes in the larger chromosome region, is the real cause of pelvic loss in sticklebacks. This region, which the scientists termed as “Pel” was then cloned and injected into unfertilized eggs of pelvic-reduced fish. The scientists did this in order to see if the region is a major determinant of pelvic formation in sticklebacks, which it ended up
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
Smith, D. G., & Schenk, M. P. (n.d.). A Dissection Guide & Atlas to the Mink. Google Books. Retrieved May 27, 2014, from http://books.google.com/books?id=kifAAgAAQBAJ&pg=PA83&lpg=PA83&dq=male+mink+reproductive+system&source=bl&ots=6Q8L-rNG76&sig=L2TpamuuykxepCG7uaLJdmyTeuM&hl=en&sa=X&ei=aa-DU8XFA8OhqAa2yIKYAw&ved=0CF0Q6AEwCA#v=onepage&q=male%20mink%20reproductive%20system&f
One hundred and fifty million years ago, large aquatic species of reptile such as the Plesiosaur dominated the ocean, and were pre-eminent predators of the sea. The branch of now extinct Plesiosaurs, or ‘near lizards’, evolved into variant closely related species specialised to take different niches in the food chain. Such species of Plesiosaur include the phenotypically similar Plesiosauroid and Pliosauroid. The physiological adaptations of the long necked variant, the Plesiosauroid, as it relates to deep sea diving, will be addressed in depth.
The main idea of this story Fish Cheeks was understanding and appreciation and having pride in one own unique culture. Tan mother invites the minsters family who happens to be her crush at the time who is Robert the minister’s son. Tan felt despaired during the entire evening, feeling ashamed of her family and non- American ways at dinner. At the end of the evening Tan’s mother tells her that she understands that she wants to like all the other American girls and handed a gift. Tan’s mother points out to her that she must not be ashamed of her difference, however, embrace these differences that she has found shame in. Overall the main idea was the differences that we are often ashamed of are the differences we should take pride in, because
I chose dolphins because they are such elegant creatures, even though wild dolphins are often dangerous. Dolphins are my favorite creatures in the world, and people ought to respect them more.
Turner’s syndrome is a genetic conditions that affects the female’s sex chromosome. In (http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001417/) Turner’s syndrome occurs when cells are missing all or part of an X chromosome. It’s common of the female patient to only have one X chromosome. Although, some individuals may have two X chromosomes but one is defective. It is thought that an estimated 1 out of 2000-2500 females suffer from this genetic condition worldwide but it’s usually females with this condition don’t survive their birth. Due to this abnormality, the genes that is defective “affect the growth and sexual development of the female” (http://learn.genetics.utah.edu/content/disorders/whataregd/turner/). However other disabilities and delays do occur even though these traits can vary case by case.
The word “monotreme” is Greek for “one-hole,” referring to the cloaca that is the exit for the urinary, reproductive, and excretory systems (Dawson, 1983). The creatures are oviparous--the females lay eggs that develop outside of her body. This paper will explain the background of the animals, the anatomy of the tract and egg, breeding behavior, and genetics behind this unique reproductive system. It will pay special attention to the similarities of the monotreme reproductive system to those of animals we are more familiar with.
Sadler, T. W., and Jan Langman. Langman's Medical Embryology. Philadelphia: Lippincott Williams & Wilkins, 2006. Print.
middle of paper ... ... World Book Inc, 2000. Davis, Lloyd S. and John T Darby. Penguin Biology. San Diego: Academic Press, Inc., 1990.
The Axolotl, a crucially endangered neotenous species of mole salamander, has adapted to fit its environment so it can easily catch food and evade predators. The Axolotl’s habitat is the lake system of Xochimilco that is near Mexico City, Mexico. This shallow, fresh water lake complex has a temperature range of 6- 20°C and a pH of 7- 12. The complex also has the Axolotl’s primary food sources of mollusk, insect larvae, and other crustaceans. However, with the introduction of foreign species such as the Asian Carp and the African Tilapia, the Axolotl now has predators that may eat and threaten it, and it has competition for the animals it usually eats. Fortunately, the Axolotl has developed adaptations that aid it in catching food and evading predators. To help it catch food the Axolotl’s teeth are shaped like cones, so that its “vacuum” action of sucking in as much water in order to also eat food is aided by the shape of the teeth, which allow it to grip, rather than chew. To aid them in avoiding predators they are able to metamorphose so that they use their lungs more than their gill, which allows them to leave very toxic waters and the predators within. Another adaption that helps them deflect any predator is that they are able to regenerate body parts that have been lost, allowing them to stay as strong as possible. Axolotl’s have adaptations that aid their survival from predators in the lake complex Xochimilco that they reside in.
The first neural induction in amphibian embryos has given the Nobel Prize in Medicine award to Hans Spemann in 1935 for his “Spemann-Mangold organizer” paper. The discovery with her student Hilde Mangold leads to establishment of a neuroectodermal primordium from where the nervous system arise involving induction of chemicals such as the fibroblast growth factor (FGF) and WNT signalling, together with inhibition of bone morphogenetic protein-4 (BMP) signalling activity to promotes neuron development. Spemann’s study has successfully identified a morphologically distinct cluster of mesodermal cell located in dorsal lip of blastophore known as ‘organizer’ which has the potential in neural induction. BMP will trigger neural induction and are formed during the gastrulation in vertebrate embryo which is secreted by ventral gastrula signalling centre (Spermann H, Mangold H, 1924). In a normal mechanism BMP binds with receptor on ectoderm cell to form epidermis. However, by inhibiting BMP, ectoderm cells will differentiate to form the neurons cells without the presence of neural inducers t...
M Dufrasne, I. M. (2013). Journal of Animal Science. Animal Genetics , Volume 91 (12).
In general, electroreceptive fishes are categorized into non-electric fishes and electric fishes (Crampton & Albert, 2005). On the one hand, non-electric fish do not possess electric organs and use passive electroreception, which is when the fish reacts to external electric stimuli (2005). On the other hand, electric fish are fishes that have specialized electric organs (electrosensory organs) present and use active electroreception, which produce or generate electrical stimuli (2005). The receptors that electric or non-electric fishes use to detect the electrical stimuli are called pit organs that are often open to the surrounding water by way of canals that are filled with an electrically conductive gelatinous substance (2005). There are two types of pit organs: tuberous electroreceptive organ, which are used in active electroreception, and ampullary electroreceptive organ, which is used in passive electroreception.
Overtime, we have heard of the little tales of the half human half fish mythical creature. They’re either these beautiful creatures just roaming around the ocean or these awful evil creatures that lure you to your death. Somewhere along the literary and mythological road, mermaids and sirens got confused into one creature: a half-woman, half-fish creature known for her beautiful singing voice. Originally, it was only the mermaid that was a half-human, half-fish creature, and a singing voice wasn’t mentioned in early myths.