HELP Genetics Question PLZ Read Additional info for the question?

Question

In tomatoes, the texture of the skin may be smooth or peach (hairy). The Ponderosa variety has fruits with smooth texture. The red peach variety has fruits with peach texture. Crosses between the two varieties produce all smooth fruits. Crosses between these smooth-fruited F1 plants produce 174 peach textured fruits and 520 smooth textured fruits. How are these skin textures inherited?

Answer 1

This is a simple case of complete dominance........1

Smooth texture is dominant over Peach texture .....2.

When a Pure (homozygous) Smooth ( SS) is crossed
with pure Peach (ss) . The result is hybrid Smooth in
F1 generation(Ss)........3.

A selfing of F1 results in Smooth to Peach in 3:1 ratio

520 : 174 is in fact 3 : 1 ratio...............4

Answer 2

OK...You have one variety of peaches that is hairy and one that is smooth. When you cross these two, all of the offspring are smooth. That says that smooth is dominant and hairy is recessive. When you cross the F1 plants, you get about a 3:1 ratio, which says that the two F1 plants were both heterozygous (something like Ss). So the smooth original plant would be SS and the hairy one would be ss.

Answer 3

Okay, the ratio between them is just about 3:1.

Make a simple punnet square of a basic dihybrid cross and you should get about 3 dominant-expressing phenotypes for every recessive-expressing phenotype.

Doing a Punnet Square is well-described HERE:
http://www.usoe.k12.ut.us/CURR/Science/sciber00/7th/genetics/sciber/punnett.htm
The TT and tt cross on that page works just like the crosses between the two fruits described, in that example, you get all Tt, which would be tall, just like you get all smooth (the dominant.)

Now, make your own punnet square of the hybid (heterozygous) plants. Since they are all Tt, you'd have Tt on top, and Tt on the side.

Take the time to learn to do a punnet square- it is very easy once it clicks and good points on your test because it sometimes looks hard at first, so some people in your class will assume it is no big deal and never get it.

It's a big deal. It's sort of the foundation for Mendelian genetics.

To verify that it is definately a 3:1 pattern, do a CHI-square. Google chi-square and genetics if you don't know how.