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I am not quite sure how to write 100% out come for the phenotype ratio after using "Punnett Square". The result from the each alleles, the dominant allele completely(100%) took over the recessive allele. How can I express my phenotype ratio?

(Let's say....Purple flower→dominant White flower→recessive)

  1. Phenotype/ Purple flower 1: White flower 0
  2. Phenotype/ Purple flower 4 :white flower 0
  3. Phenotype/ Purple flower 4
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closed as unclear what you're asking by Remi.b, AliceD, James, fileunderwater, The Last Word Oct 14 '15 at 6:58

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ I am voting to close because It is a question of language and not of biology. $\endgroup$ – Remi.b Oct 11 '15 at 23:44
  • $\begingroup$ You could write "ratio of purple to white flower 1:3" I suppose. Also you should clarify whether you want to express such ratio in a sentence or as a list of such ratios. $\endgroup$ – Remi.b Oct 11 '15 at 23:44
  • $\begingroup$ Note btw, that there are a few typos in the title of your post. $\endgroup$ – Remi.b Oct 11 '15 at 23:46
  • $\begingroup$ I understand the how to express the ratio of the our come of 1:3.....but I was not quite sure how I should do to express when the outcome is 100%......I guess I could do with "Purple flower4: white flower 0".....!? $\endgroup$ – Runa Oct 12 '15 at 1:51
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    $\begingroup$ @Remi.b Just to clarify, a ratio or 1:3 (not 1:4) corresponds to 25% white and 75% purple flowers. $\endgroup$ – Harry Vervet Oct 12 '15 at 3:29
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The phenotype ratio would be 4:0.

You did not include the complete example including the genotypes, but an example that might produce this result is:

P is a dominant allele that produces purple flowers, and pp homozygotes are white.

    P    p
  -----------
P | PP | Pp |
  -----------
P | PP | Pp |
  -----------

The genotype ratio is 2:2:0 (2 PP : 2 Pp : 0 pp) meaning there are 50% PP and 50% Pp.

The phenotype ratio is 4:0 (4 purple : 0 white) meaning there are 100% purple and 0% white flowers.

To keep things simple, you do not need to reduce the ratio to the lowest terms (in other words, the sum of the numbers in the ratio should equal the number of boxes in the Punnett Square). It would not, however, be incorrect to reduce the genotype ratio to 1:1:0 and the phenotype ratio to 1:0.

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  • $\begingroup$ Thank you so much for your help! Especially giving an example of genotype.! I can clearly see the difference now. And yes....I should have given my example a lot more clearer.... one more worries....the way I should answer fully...is going to be... " purple flower 4 : White flower 0" for the phenotype...? If you could help me once again.... $\endgroup$ – Runa Oct 12 '15 at 3:15
  • $\begingroup$ @Runa I do not understand what you are asking now. It is a matter of preference whether you reduce the ratio to lowest terms (that is 1:0). However, from your comments it appears your instructor is keeping things simple by making sure the number of boxes in the Punnett Square add up to the sum of the numbers in the ratio, which is why I suggested the best answer is 4:0. $\endgroup$ – Harry Vervet Oct 12 '15 at 3:24
  • $\begingroup$ Yes...you are very correct... My worries are not about the number anymore but how to express"Biology term ratio"(Thanks you as you explained, it made all clear for the number.) it is just about how to answer the question, how to write....(I was not sure if there were the big rule about "how to write the biology term of the ratio")...I guess I am little like " being-worry-too -much"... $\endgroup$ – Runa Oct 12 '15 at 3:41

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