Punnett Squares

Genetics as it applies to evolution, molecular biology, and medical aspects.

Moderators: Leonid, amiradm, BioTeam

Post Reply
guybrush
Garter
Garter
Posts: 5
Joined: Mon Feb 22, 2010 10:28 am

Punnett Squares

Post by guybrush » Mon Mar 22, 2010 5:29 pm

Hi,

I have completed some punnett squares and was wondering can you check i am on the right lines.

In Punnett Square 1. Yellow seeded plants were crossed with green seeded ones to produced all yellow plants.

My punnett square read: Y Y for yellow and y y for the green ones and i came up with: Yy - Yy- Yy- Yy. The question states that all the plants turned out Yellow.

In the next square i used Y y down one side, and Y y going across. My answers were YY- Yy- YY- yy. The question states it gives a 3 to 1 ratio in Y's (yellow) favour.

Finally i am asked to cross a green seeded plant with a heterozygous (say Yellow) seeded one. This is where i am a bit confused.

Will the green seeded one be yy, and the heterozygous one be Y y? My answers read: yY- yy- yY- yy. Is this correct? This would mean 2 of the plants would be green (yy), and the other 2 would be Yellow (Yy).

Am i on the right lines?

User avatar
JackBean
Inland Taipan
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

Post by JackBean » Mon Mar 22, 2010 5:56 pm

I think you have everything correct. Yellow is dominant, so it can be either YY or Yy, whereas green is yy and all your squares look fine to me.
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

guybrush
Garter
Garter
Posts: 5
Joined: Mon Feb 22, 2010 10:28 am

Post by guybrush » Mon Mar 22, 2010 6:35 pm

Thanks, much appreciated for the reply.

User avatar
jwalin
Coral
Coral
Posts: 438
Joined: Tue Sep 15, 2009 3:43 pm
Location: ahmedabad, gujarat, India

Post by jwalin » Tue Mar 23, 2010 6:26 am

yopu have done everything right...
but one question why did you draw the second square ??? it want necessary :roll:
it isn't what you do that matters but it is how you do it

User avatar
JackBean
Inland Taipan
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

Post by JackBean » Tue Mar 23, 2010 7:44 am

another useless post? I'm warning you, I will start deleting them.
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests