Genetics Quiz

For those who might enjoy it, I've made up a quiz on genetics and inheritance. If you have a decent grasp of the material in my genetics/inheritance tutorial, you should be able to answer most of these, and deduce the answers to the rest of them.

I'll give out the answers/explanations on Sunday for anyone who wants to check their work. If you have questions or need clarification/re-explanation of any of the questions, ask away.

Note: unless otherwise mentioned,

• all mutations/traits are recessive to "normal,"
• all mutations only have one wild-type and one mutant allele,
• and all mutations are inherited in simple fashion.

Basic:

Define Heterozygous and Homozygous.

What is the difference between Phenotype and Genotype?

What is the difference between Dominant, Codominant, and Recessive?

What are the possible genotypes for a simple trait called A?

If a trait is recessive, what is the genotype of an animal that expresses this trait?

If a trait is dominant, what is the genotype of an animal that expresses this trait?

If a trait is codominant, how many phenotypes exist for the possible genotypes?

If an animal is het for a recessive trait, what does it look like?

If you breed "A" (an A-mutant, which shows that trait) X "het for A" what will the offspring look like?


Intermediate:

Define Allele.

Define Locus.

When both parents are het for the same recessive trait, what is the best description of their normal-looking offsprings' genotype?

What do P, F1, F2 mean?

When both parents are "double-het for A and B,"

• What is the expected ratio of phenotypes in the offspring?
• How would you describe the genotypes of the offspring that only express mutation B?

If an animal has never been bred but is known to be het for trait A, what can be said about its parents?

Where A is recessive and D is a dominant trait: breeding "A het for D" X "het for A" will give you what results?


Given that 3 alleles exist for trait A:

• A1 (dominant wild-type),
• A2 and A3 (recessive to A1, and codominant to each other)

How many possible genotypes are there? (example: 11, 12, 13, etc.)

How many possible phenotypes are there?

If you breed "22" X "33":

• What will the offspring look like?
• Are the offspring homozygous or heterozygous?

What trait(s) in cornsnakes resembles this trait?



Advanced:

What are the advantages and disadvantages of inbreeding?

You find a wild amelanistic male, bring it home, and breed it to a never-been-bred amelanistic female in your collection. All of the offspring are normal. Explain.

While in the 5th generation of line-breeding normal cornsnakes, you mate 4 brother/sister pairs. Every clutch results in 20 hatchlings. In all but one clutch, the offspring are all normal, as you would expect. Out of 20 of the hatchlings in the other clutch, 5 of them show a new (never-before-seen) trait.

• What is most likely to have happened?
• What is the most likely mode of inheritance of this trait? (simple/complex, dominant/codominant/recessive?)
• Where would you suspect the trait to have originated?
• Statistically, how many of the 80 offspring would be het for this new trait?

A new recessive allele appears in a wild population. When expressed, this trait makes survival in the wild impossible. At what point does being heterozygous for this trait create a selection disadvantage?

Wow that was some test. I feel like I'm back in genetics class. Strangely, that was a lot of fun. I won't post my answers though so everybody gets a fair shot

Thanks!

much... tooo... early... to... think... rationally... need... coffee... head... hurts... will... return... later...
by the way, that^^^^ is great. thanks! bet you get alot of visits to your site ---jim

n/p

Thanks for the quiz. It took me most of the morning, during which time I was to do the laundry and clean the house. These tasks got effectively postponed to next week. Cool. Never pass up a good reason to procrastinate.

AURGG...TO...ADVANCED..FOR ...MY...12...YEAR..OLD...BRAIN.... CAN'T UNDERSTAND...GOING...TO...SLEEP HELP!!!
SORRY...TO...ADVANCED..FOR..ME? ...MAYBE...WHEN...I...BECOME..A..HERPTROLOGST(PERS ON WHO STUDYS HERPS)

THANKS ANYWAY
MUST GO STUDY FOR MATHH QUIZ

X=8453=G+JFYEBN+MCINSG%748#@^KDYBSS+(It basiclly means I'm confused could you write that in simpiler terms possibly?

Maybe? ?????

at what point does it become a selection disadvantage to be het. for this trait? seems to me that it would be a disadvantage for your young for you to be het. at any point where you are not the only gene-carrier in your geographic gene pool. anythng beyond this is only decreasing the odds for survival of your offspring. i don't think this is what you are looking for though.....

If we pass this can we get any college credit for it? Man, I'd better start reading your tutorial.

Originally posted by nicky
It basiclly means I'm confused could you write that in simpiler terms possibly?

Which one(s) are you referring to? It does require that you understand the terms: Heterozygous, Homozygous, Phenotype, Genotype, Dominant, Codominant, Recessive, Allele, and Locus. It would take paragraphs to describe some of those without using this terminology.

Also, it requires knowing the basic idea of inheritance (how genes get from parents to their babies.) I'm not trying to insult anyone, I just have no idea who has how much knowledge of what...

-----

Originally posted by jim
at what point does it become a selection disadvantage to be het. for this trait? ...

It's hard to word that without a long explanation. By "selection disadvantage" I'm addressing the entire process of selection, which involves which animal's genes get passed on based on who can and cannot survive long enough to reproduce. (If that makes any sense of it...)

But yes, you got exactly what I was looking for.

oops, sorry for posting that then. i thought maybe you were looking for something a little more specific... guess i should have waited for the answers.