× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
a
5
k
5
c
5
B
5
l
5
C
4
s
4
a
4
t
4
i
4
r
4
r
4
Home Q & A Board Biology-Related Homework Help Cell Biology
New Topic  
topix129 topix129
wrote...
Posts: 22
Rep: 0 0
11 years ago
black flies are dominant trait; white flies are a recessive trait. when a pure black fly is crossed to a white one, what fraction of the offspring is expected to be heterozygous? use the letter ''B''.
Read 586 times
1 Reply

Related Topics

Replies
wrote...
#1
11 years ago
Pure black fly means the fly is homozygous dominant (BB) for the trait.

White flies have to be homozygous recessive (bb) because recessive traits are only expressed when they are homozygous.

So the cross of a pure black fly with a white fly is this: BB x bb

Use the Punnett Square method:
   B   B
b Bb  Bb
b Bb  Bb

As you can see, we have 4 Bb, which means 4/4 will be heterozygous for the trait!
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  1340 People Browsing
 110 Signed Up Today
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Related Images
  
 301
  
 1960
  
 1063
Your Opinion
What's your favorite coffee beverage?
Votes: 274
Previous poll results: What's your favorite math subject?