From: Mugan, Paul
Sent: Tuesday, January 05, 2010 9:52 AM
To: 'Sigrid Brus'
Subject: RE: Brus, Sigrid 1st Bio

BRUS!

    Do the SQUARE!   (but backwards)

 

    If I have about 150 grey flies and about 50 black flies…  That’s a 3:1 ratio!

 

    A 3:1 ratio would result from a crossing of two heterozygous grey flies…  Gg X Gg

 

     

 

G

g

G

GG

Gg

g

Gg

gg

 

    Thanks for the question!

 

MUGAN

 


From: Sigrid Brus [mailto:wsr_panda5@msn.com]
Sent: Monday, January 04, 2010 9:54 PM
To: Mugan, Paul
Subject: Brus, Sigrid 1st Bio

 

I was taking one of the tests and I got the following question wrong. Could you explain why my thinking is wrong?:
 

In the fruit fly, gray body (G) is dominant over black body (g). Two gray flies were mated. 158 gray bodied flies and 49 black bodied flies were produced. The parents probably were:

  1.   GG x GG
  2.   Gg x Gg
  3.   GG x Gg
  4.   Gg x gg