[LeDave]

I am going to be in big trouble if I don't keep up with my genetics class. My teacher is very confusing and so is this class! I need some help on genetics.

I have a question.

There are two homozygous parents that produced F1 offsprings that are heterozygous. The Parents produced gametes of RY, RY, ry, ry, and Ry, Ry, rY, rY for the F1 generation.

Now with RyYy showing up throughout the monohybrid cross punett square making all heterozygous. When the F1 gametes are placed into the dihybrid cross, how does it get a horizontal set of RY, Ry, rY, ry and a vertical set of RY, Ry, rY, and ry. I'm so confused.



I did a Meiosis Diagram for another F1 generation and the gametes produced were SV, sV, sv, sv, Sv, Sv, sV, sV. However I don't want to know how to put these in the correct spots for the punett square yet for these, but I don't want to know the exact answer because I want to do it myself. To do it myself, I want to understand the one shown above first. Thanks!

[Rupert]

I'm just a plumber, so you can't really expect me to be of any help here...I do know that shit does not run uphill...but if you have a good solids pump, you can pump it most anywhere.

The only thing I recognized in your chart was Sv...I shoot mainly in Sv mode, very nice Pentax setting, allows quick ISO change for fast changing light situations on the front dial and aperture on the rear. Covers about all an old Squirrel shooter ever needs.

Good luck on your problem, if you don't solve it you can always be a plumber...even Joe the Plumber has made a fortune and he doesn't know shit about plumbing.
Regards!

[Sailor]

Sorry - I can provide no help, but lots of sympathy. I know that genetics is to biology what P-chem is to chemistry; I had many friends pulling out their hair over genetics.

If you want to drop this class and take organic chemistry or polymer chemistry, then I'm your man.

Jer

[Rupert]

Sorry - I can provide no help, but lots of sympathy. I know that genetics is to biology what P-chem is to chemistry; I had many friends pulling out their hair over genetics.

If you want to drop this class and take organic chemistry or polymer chemistry, then I'm your man.

Jer

That's a decent offer, and one he might be wise to consider, but mine is much easier...all you need to remember is...shit...uphill...downhill.....possibly pumps...collect the cash!
Regards!

[little laker]

I'm just a plumber, so you can't really expect me to be of any help here...I do know that shit does not run uphill...but if you have a good solids pump, you can pump it most anywhere.

That's not what I learned while building condo's.
I learned that shit goes downhill, and everyone starts at the bottom
Needless to say, that was one thing I never wanted to start below, so I've never done any real plumbing

[jeffkrol]

I am going to be in big trouble if I don't keep up with my genetics class. My teacher is very confusing and so is this class! I need some help on genetics.

I have a question.

There are two homozygous parents that produced F1 offsprings that are heterozygous. The Parents produced gametes of RY, RY, ry, ry, and Ry, Ry, rY, rY for the F1 generation.

Now with RyYy showing up throughout the monohybrid cross punett square making all heterozygous. When the F1 gametes are placed into the dihybrid cross, how does it get a horizontal set of RY, Ry, rY, ry and a vertical set of RY, Ry, rY, and ry. I'm so confused.



I did a Meiosis Diagram for another F1 generation and the gametes produced were SV, sV, sv, sv, Sv, Sv, sV, sV. However I don't want to know how to put these in the correct spots for the punett square yet for these, but I don't want to know the exact answer because I want to do it myself. To do it myself, I want to understand the one shown above first. Thanks!

Eek been ages... and probably wrong answer to your question but here goes nothing
Parents RRyy x rrYY or RRYY x rryy produce 4 RrYy offspring (f1)
crossing that RrYy x RrYy would get you the above table (f2 gen),,,,,,,,,,
just wiki it
Dihybrid cross - Wikipedia, the free encyclopedia
cute pic.........

http://en.wikipedia.org/wiki/Law_of_Independent_Assortment#Law_of_Independent_Assortment

[Ratmagiclady]

Fortunately, there's a genetics person in the house!

Basically, it seems you may have gotten something written down wrong somehow, by how it's written out here.

Introducing mah sweetie!

Science!




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Well, your first problem is that if you have two parents, and they're both homozygous at two different loci, then you can only have one possible F1 genotype:

RRYY x rryy --> RrYy

Notice how in RRYY you can only end up with RY as a gamete, and in rryy you can only end up with ry as a gamete. So no matter what, the F1 organism will have a genotype RrYy.

But for F2, you can produce a lot of different combinations:

RrYy x RrYy --> (all that stuff in your chart)

Going through the same process as for the parents (remember, each locus can move separately from the other), it might make more sense now how you can get RY, Ry, rY, and ry along each axis.

---------------------------------

Hope that's helpful.

Fortunately, there's a genetics person in the house! Well gentics gone awry anyway.

Basically, it seems you may have gotten something written down wrong somehow, by how it's written out here.

Introducing mah sweetie!

Science!




----------------------------------------------------------------

Well, your first problem is that if you have two parents, and they're both homozygous at two different loci, then you can only have one possible F1 genotype:

RRYY x rryy --> RrYy

Notice how in RRYY you can only end up with RY as a gamete, and in rryy you can only end up with ry as a gamete. So no matter what, the F1 organism will have a genotype RrYy.

But for F2, you can produce a lot of different combinations:

RrYy x RrYy --> (all that stuff in your chart)

Going through the same process as for the parents (remember, each locus can move separately from the other), it might make more sense now how you can get RY, Ry, rY, and ry along each axis.

---------------------------------

Hope that's helpful.

But what about the typical recessive gene that leads to rrryy/\2 and only shows up every 21st generation to yeild a greenish yellow bitter gay llymon? Have you forgotten about that?

Sorry bub, can't really help since the last time I was studying genetics was to breed in certain desirable traits into angelfish to get a gold veiltail. Gene Lucas, Ph.D. seem to make it mighty easy at least while studying betta genetics.

[southy]

I did a Meiosis Diagram for another F1 generation and the gametes produced were SV, sV, sv, sv, Sv, Sv, sV, sV. However I don't want to know how to put these in the correct spots for the punett square yet for these, but I don't want to know the exact answer because I want to do it myself. To do it myself, I want to understand the one shown above first. Thanks!

So I'm going to assume that the first 4 are from one parent and the second 4 are from the other parent. The one thing about sexual reproduction is that gametes from the same parent can't recombine.
Practically, this means that all the gametes from one parent go across the top( SV, sV, sv, sv), and the gametes from the other parent go along the side(Sv, Sv, sV, sV). In your original diagram, this is labeled as male parent and female parent.

Then multiply out and you should get your result. Don't forget to combine and simplify like phenotypes and genotypes.

Code:

   SV    | sV   |sv   | sv   |
Sv| SSVv | sSVv |sSvv | sSvv| 
Sv| SSVv | sSVv |sSvv | sSvv|
sV| SsVV | ssVV |ssvV | ssvV|
sV| SsVV | ssVV |ssvV | ssvV|

Alternatively, you can deal with fewer terms by combining first, then multiplying

Code:

         SV (1/4) | sV (1/4) | sv(1/2) |
Sv(1/2)| SSVv(1/8)| sSVv(1/8)|sSvv(1/4)| 
sV(1/2)| SsVV(1/8)| ssVV(1/8)|ssvV(1/4)|

Hope that helps,
-s

[Rupert]

Damn I'm glad I stuck with plumbing.....this shit is way too omplicated for my simple brain. Just the plain old shit is much easier....and I bet it pays better too. Making wrinkled lemons...or limes....how can that be as profitable as installing a septic system?
Regards!

[Sailor]

That's a decent offer, and one he might be wise to consider, but mine is much easier...all you need to remember is...shit...uphill...downhill.....possibly pumps...collect the cash!
Regards!

That's pretty much the basis of Physical Chemistry but just without the math.

Jer

[rhe]

The homozygous parents are RRYY (round yellow) and rryy (wrinkled green) or RRyy (round green) and rrYY wrinkled yellow).
The gametes from the first parent are all the same: RY
The gametes from the second parent are all the same: ry
The gametes from the third possible parent are all: Ry
The gametes from the fourth possible parent are all: rY

In the dihybrid crosses the choices fro the male gametes (across the top of the grid) are therefore RY, ry, Ry, and rY.

Likewise in the dihybrid crosses the choices for the female gametes (down the left side of the grid) are therefore also RY, ry, Ry, and rY


By the way...Gregor Mendel fudged his results!!!

[forensicscientist]

LeDave,

If you are having difficulties, I'd suggest....

Amazon.com: Genetics Problem Solver (Problem Solvers) (9780878915606): The Staff of REA: Books

you can probably find it in the University book store, or the library. I would get them from time to time when my Profs weren't the best.

Now that I'm a part time Prof, I recommend them to my students.


good luck,
mark

[Rupert]

I have always found genetics to be extremely interesting, although I never took enough interest to become educated, beyond osmosis, in the actual study.
My Grandad, a builder and great mathematician, but not well educated by today's standards, was very involved in horticulture and animal husbandry, and I remember him at break time or lunch when we were on a project with his glasses on and a book on genetics open while in deep thought and a pencil and paper in hand to write down his thoughts or findings for future use. He spent his off time working with plants and cultivating new strains......I should have listened more, but was young and had other things like fast cars and girls on my mind. I have often wished I could bring my Grandad back and give him the wealth of information we have today, and the education he lacked. He was the most influential person in my life, and a fine and honorable man without a single enemy in the world......heck, I just wish I could be like that now.....half or more people on this Forum want to eliminate me! Some like Gooshin wish cancer on me.....George wants to cut me in half....somewhere I went all wrong....but those damn Squirrels, they all love me! I think my wife does....but you can't ever be too sure.....I guess Squirrels will have to do for old Rupert....
Regards!

[LeDave]

Thanks for the help everybody. I have another question.

Since the F2 shown in the punnett cross is (I think this is how it's suppose to be):

Code:

   SV    | Sv   |sV   | sv   |
SV| SSVV | SSVv |SsVV | SsVv| 
Sv| SSVv | SSvv |SsVv | Ssvv|
sV| SsVV | SSVv |ssVv | ssVv|
sv| SsVv | Ssvv |ssVv | ssvv|

It gives a phenotypic ratio of 9:3:3:1 out of 16 when you do the punnett square.

This is from the F2, what would the gametes of the F1 generation produce to allow the F2 to put gametes in the punnett square like that? Is it SsVv and SsVv?