My final exam for general biology is in 3 hours and I still have one question that I can't seem to answer on my review. I have to pass the final to get credit for the class. The question is..."What is an example of evolution using genetics?"To which I answered,"A large number of houseflies died after the introduction of DDT; most houseflies born today have a resistance to DDT."For reference, DDT is the chemical in bug spray that kills bugs.My instructor has already told me via E-Mail that my answer is right but he wants me to show genotypes. I totally sucked at the chapter with genotypes and phenotypes. Can someone help?Thanks!
SuesquatchRN, BSN, RN 10,263 Posts Dec 10, 2007 See if this helps.http://en.wikipedia.org/wiki/Genotype-phenotype_distinction
JaredCNA, CNA 281 Posts Specializes in ICU. Med/Surg: Ortho, Neuro, & Cardiac. Dec 10, 2007 Thanks for the site. It's a good reference. Now that I understand genotype more, I'm still having a hard time "showing the genotype." I don't know if that is like...XXDD = male resistant to DDTXYDD = female resistant to DDTXXDD x XYDDAnd then do the punnet square or whatever. I asked him for help on that part and he said he can't help me. No one in my class is available right now.
SuesquatchRN, BSN, RN 10,263 Posts Dec 10, 2007 I don't know what he means by "showing the genotype." Is the Punnett square the Mendelian square?
SuesquatchRN, BSN, RN 10,263 Posts Dec 10, 2007 Okay, I did a little poking around via Google and these types of questions want the Punnett square shown.
JaredCNA, CNA 281 Posts Specializes in ICU. Med/Surg: Ortho, Neuro, & Cardiac. Dec 10, 2007 I don't think we covered Mendelian Squares, so I guess he's looking for a punnet square.Ack, so lost. How would I cross maternal and paternal if I don't know if they carry the DDT-resistance gene, if they don't carry it, etc.?
SuesquatchRN, BSN, RN 10,263 Posts Dec 10, 2007 I don't think we covered Mendelian Squares, so I guess he's looking for a punnet square.Ack, so lost. How would I cross maternal and paternal if I don't know if they carry the DDT-resistance gene, if they don't carry it, etc.?Well, at least one of them has to carry it if it's a dominant trait, both if it's recessive. Right?
SuesquatchRN, BSN, RN 10,263 Posts Dec 10, 2007 The Punnett square is what I call the Mendelian square, Jared.
JaredCNA, CNA 281 Posts Specializes in ICU. Med/Surg: Ortho, Neuro, & Cardiac. Dec 10, 2007 DD x dd D Dd Dd Ddd Dd DdMaybe? But I still don't know if the gene is dominant or recessive in mother or father.
JaredCNA, CNA 281 Posts Specializes in ICU. Med/Surg: Ortho, Neuro, & Cardiac. Dec 10, 2007 Well, does the monohybrid cross above look alright to you? The father has the dominant gene.Thanks so much for the help.
