Heya, Been a while since i was here... Been studying like a mad thing the past 2 years Please Register or Log in to view the hidden image! Anyway, have become stuck on an assignment question that i just cant seem to nut out. The question is as follows: "Giving examples, explain how a gene's expression (phenotype) may be affected by the environment in which an animal (dog or cat if you like) lives" Sounds simple enough yes? Well, i understand basic basic basic genetics in relation to fish. I understand phenotype and genotype. I assume it is referring to plasticity, but i have no texts on the matter. At its most basic level, what would be an example? All i keep coming back to is food and sunlight/weather, but there has got to be more to it. Would food be included as environment? does phenotype include behaviour or just visual stuff? Am i including wet dog/dry dog or sunspots?:bugeye: I know this sounds like "please do my homework" but just need a good boot in the right direction as i am nearing burnout on this course. Thankyou VERY much to anyone that replies Please Register or Log in to view the hidden image!
If you had a pet plant your homework would be a lot easier to answer. Fighting fish might be a suitable example. They are quite plain if you keep them away from other fish and in the dark, yet when they are shown another fighting fish their colours change, as a result of the gene pathways and producing pigments. –hence their environment has a dramatic effect on their phenotype. But this depends on the definition of phenotype. (Phenotype defined by human genome project); The observable traits or characteristics of an organism, for example hair colour, weight, or the presence or absence of a disease. Phenotypic traits are not necessarily genetic.) So if weight is a phenotype, then bringing your dog up in a situation where he’s bored and eats because its all he can do, is giving him a phenotype which is not genetically determined. There are also myths such as if you walk a pup too much they have longer legs than they should for that breed. My problem with answering this question is that it seems to only be asking for an individual’s response and variation between phenotype, genotype and environment, not an answer on a group/species level and so not a natural selection answer. Plants would be a lot easier to illustrate this because the same genotype gives different phenotypes depending on altitude, soil types ext. Animals do this as well, but its poorly understood and not widely excepted because it’s not in keeping with good old genetic determinism Please Register or Log in to view the hidden image!
Animals do this as well, but its poorly understood and not widely excepted because it’s not in keeping with good old genetic determinism do elaborate. hold nothing backPlease Register or Log in to view the hidden image! thanks
I’m using the term ‘Genetic Determinism’ to refer to the idea that our genes determine who and what we are at every level: physical, emotional, and behavioural. And as such minimises the importance of the environment in ‘determining’. I have issue with the term ‘determine’. Its quite often said that sex is genetically determined, with some reference to the X and Y chromosome, which is bizarre because that would be chromosomal sex, and then term genetic sex could be used to indicate if the person had SRY, or a range of other genetic variations. However the role that environment plays in forming and constructing the persons sex is minimised (womb hormones, peer recognition ext). There is a very interesting story to be told how the SRY came to be seen as the TDF –a mendailan constriction, the essence of difference between male and female. I think environmental factors are poorly understood because socially we are less willing to change our environment. So the public and politicians drive research money to fund genetic determinist research because it gives society a sense of nature, and fate. I don’t think it’s a strongly predominate view in science, but it does seem to be one which gets exported by the media very successfully. I’m in a rush so that’s all I can write at this moment and it’s off topic…Please Register or Log in to view the hidden image!
Thanks Weebee Please Register or Log in to view the hidden image! I also found a lot of info on plants, but, seeing as its a Veterinary based course, i think that if i fronted up with plant examples, they might not be too impressed Please Register or Log in to view the hidden image! Glad Bettas came up, they are the basis of all things i know about genetics (although, that isnt very much, as you can see.) Would you class quality of food as 'environment'? What about owner intervention (flea treatment/etc)? I think i can nail this one now (Although it is aimed at the individual, i do have permission to take it to natural selection, but seeing as there is a 2 page limit, i'll be hard pressed to get in this bit Please Register or Log in to view the hidden image! I think he just doesnt want to mark much...)
Sure quality, and quality of food and ownder intervention would be environment. Please Register or Log in to view the hidden image!
Most known examples in animals ... or at least humans ... relate to diseases. Genetic predisposition to diseases, such as heart attack, can still be mitagated by behaviors like eating. Diabetics can go blind if untreated, but with use of insulin and controlled sugar consumption can avoid such problems. Weight is a good example. Cat's and dogs shedding is an example. Entrainment to a certain sleep cycle (or eating cycle) is an example (at least if regulation of gene expression is considered sufficient). If you want to read an interesting paper and have access to developmental biology check out: http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=11319853&dopt=Abstract
Yes scott has one. he also wrote a reponse to one of my lectures... Response I met him several times.
The Siamese cat (and all such with the Himalayan markings) have a pigmentation process that responds to temperature - that's why their nose, ears, tail and feet are darker than their body. An experiment could be performed where a cold patch was placed on a Siamese cat's back for a month or so, after which there would be a dark patch on the cat's back were the cold object rested. Dosing salamanders with vitamin A was found to cause them to heal more quickly than normal, and also to grow extra limbs. Good old axolotl.
I always knew I was particularly evolved - my belly button collects more fluff than anyone else I've ever met, each day I have essentially a piece of felt in there.
Phenotype is affected as soon as there is conception, or in the case of asexual animals and plants, as soon as the embryo or seed starts to form from the genes (the genotype). Phenotype is determined by environmental factors from the moment of conception till the day we die by many affects and reasons: nutrition, temperature, humidity, pollution, drugs (drug abuse), radiation, ultraviolet ray penetration, aging, and the list goes on and on.
