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Confused--phenotype with more than one gene from each parentModerator: BioTeam
5 posts • Page 1 of 1
Confused--phenotype with more than one gene from each parentOkay, so we started on punnet squares and such in Biology. I understand how to to it when I only have one gene from each parent, but what about two? When I work it, I get an answer that (in my ignorance) doesn't really make much sense.
Say, for example, I have a heterozygous tall (Tt), purple-flowered (Pp) plant crossed with a short(tt), white-flowered (pp) plant. When I do the square, I get the possibilities of Pptt, Pppp, Tttt, and Ttpp. But this doesn't look right to me, because one of them does not have a specified flower color (Tttt), and another result does not have the height specified (Pppp). I am attempting to find the phenotype, and I have no idea what I would say with these results. I cannot ask my teacher, as we're on vacation. My textbook doesn't go any further than one gene from each parent. What am I doing wrong?
Re: Confused--phenotype with more than one gene from each parent
Three answers and noone says, how to do it actually OK, you get one plant TtPp and the other ttpp. So, in first case, you can combine any of T or t and P or p, that is TP, Tp, tP, tp TtPp, Ttpp, ttPp, ttpp http://www.biolib.cz/en/main/
Cis or trans? That's what matters.
Re: Confused--phenotype with more than one gene from each parentWhen you set up a punnet square to find out the various outcomes, the allelic combination in the gametes should be properly mentioned.
Here TtPp the heterozygous parent forms 4 types of gametes- TP, Tp, tP and tp; whereas the other parent with genotype ttpp forms only one type of gamete- tp. So now put the punnet cross with: TP, Tp, tP, tp x tp You will get the following : 1 TtPp: 1Ttpp: 1 ttPp: 1 ttpp which is nothing but 1 tall purple: 1 tall white: 1 short purple: 1 short white. Now is that clear? Vijeta!!
5 posts • Page 1 of 1
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