Biology/Dihybrid crosses
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Question
could you please check these and let me know if i did them right
what are the genotypic and phenotypic results for these Dihybrid crosses
BBRR x bbrr answer BbRr
Bbrr x bbRr answer BbRr Bbrr
bbRr bbrr
BBRr x BbRr answer BBRR BBRr BbRR BbRr
BBRr BBrr BbRr BBrr
BbRr x BbRr answer BBRR BBRr BbRR BbRr
BBRr BBrr BbRr Bbrr
BbRR BbRr bbRR BBRr
BbRr Bbrr bbRr bbrr
Jim, thank you for using AllExperts and I'll give you some advice as to your question.
I don't answer homework questions directly, but there is a simple, nifty way to check dihybrid crosses: find all the possible combinations for the cross given. You don't have to find the ratio of results; that makes the problem quite a bit easier.
For instance, in the first example, is there any other way you could combine BBRR and bbrr? Nope, BbRr is the only possible combination (remember that one allele comes from each parent).
What possible combinations could you get from Bbrr and bbRr? Look at the b's first. You could have Bb and bb. Look at the r's next. What could you have there? Then combine the two. Repeat many times (this is the most difficult step--it's tedious, rather than difficult), and you're done!
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Answers by Expert:
John Locke
Expertise
I will answer all biology-related questions through the undergraduate level. I will explain unclear concepts and suggest approaches to solving problems, but would prefer not to completely solve homework problems for you. If you are completely stumped on homework, tell me what you already know and I will help you as much as possible. Please do not ask me for ideas on school research projects; part of research is determining a suitable area of investigation, and that's not a task that should be completed by someone else. Please don't simply send me your homework for solutions. If you are having difficulty after you have started an analysis, I will be happy to direct your thinking; in particular, I would prefer to not simply solve pedigrees for students, but I will be happy to assist in solving pedigrees that you have already started. If you don't understand how to analyze a pedigree, I'd highly recommend watching this video, in which a biology professor explains the basic concepts of pedigree analysis: http://www.youtube.com/watch?v=HbIHjsn5cHo
Experience
I have a BS in Bioengineering with a concentration in Chemical Engineering (which included a heavy focus on biology), and have taught biology, biochemistry, and related subjects for some time now.
Education/Credentials
BS Bioengineering, Penn State University
MCAT/DAT/OAT Instructor
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