The phenotype is the expression of the genotype. For example, a person with brown eyes could have a genotype that codes for blues eyes and brown eyes. Brown eyes is the expressed gene, because it is dominant, that is the phenotype. A person with blue eyes has a genotype that codes only for blue eyes, the phenotype is blue eyes. And in this case the phenotype and genotype match because blues eyes is recessive. Sometimes environmental factors influence the phenotype and sometimes they don’t. There are a number of genes that are influenced by environmental factors, like height. However, it should be noted that if your genotype codes mainly for shortness you will be shorter, regardless of environmental factors–including nutrition. On the flip side, if genes code for tallness you will be taller. The influence that nutrition has is that you will not be as tall as you could be.
My genotype is usually Levis, I like them better. My phenotype is private, thanks very much, and I’m not sharing with anyone other than my wife.
[Sorry, netajs, welcome to the Straight Dope Message Boards with an interesting comment. I can’t help being a smart ass sometimes. ]
For those of you out there who don’t know, you are usually sharing your genotype with your wife (and more importantly with your children). Your phenotype you share with everyone…unless you dye your hair.
Sorry, I meant to make it more like a question. But in the end it was more a clarification of a statement made in the article about midget animals.
"In these species, development and size are under environmental control (rather than genetic control–if you remember your biology, this is the distinction between ‘phenotype’ and ‘genotype’). " Written by SDSTAFF Doug.
My point is that both phenotype and genotype are tied to genetics and are both under “genetic control,” if you will. Phenotype is the expression of the genes. Things that are under environmental control would be like scars because a person may not necessarily sustain a cut which thus produces a scar (however, how you heal is controlled by genes). This comparison is probably closer to the one that Mr. SDSTAFF Doug was trying to make. Plants become “midgets” when subjected to an environmental control like over-grazing or pruning (in the case of bonsais). Much like a person scarring, the growth pattern of a plant is determined by genes. This is not, however, a phenotype in the purest sense because phenotypes are not solely dependent on environmental influences.
Really, I just put this out there for science’s sake because I hate misinformation. (If you haven’t noticed, I may also get a little lost in the details.) However, I welcome any comments or discussion.
netajs is right, this statement is incorrect. A phenotype is a physiological characteristic or behavior, while a genotype is the underlying genetic makeup that to a large extent determines that phenotype.
Environment can determine a phenotype to a large extent as well. Some flowers, based on their genotype, are capable of being pink or blue depending entirely on the condition of the soil they are planted in. So environment and genotype both play a role in determining the phenotype.