February Genetics Quiz

Inspired by the Genetics Survey on Gene Expression and an inquiry from the CanineGenetics-L yahoo group, I figure it might be fun to post an occasional genetics quiz to reinforce some of the concepts covered on this blog and provoke discussion of the sorts of genetics knowledge that is most helpful to dog enthusiasts.

The results are not tracked, it’s completely anonymous, and the correct answers will be revealed tomorrow. I tried several automated quiz plugins but they are a pain, so we’ll just go old school.  If you run across an answer that you want to discuss, do leave a comment.

February is the month of sweethearts, so there’s no better time to bone up on what happens when love is in the air and dogs are swapping genes. For the inaugural monthly quiz, here are some questions long time readers of the blog should be able to answer.

Multiple Correct Answers are accepted and often required.


Question 1

Inbreeding leads to:

Increased homozygosity.

Increased expression of recessive traits.

Decreased expression of dominant traits.

Increased heterozygosity.

Question 2

An allele:

Is one of possibly many variations of a gene.

Can be recessive.

Can be dominant.

Is a synonym of “gene.”


Question 3

A gene:

Is a unit of heredity that is transferred from parent to offspring.

Controls the transmission and expression of one or more traits.

Can code for multiple and otherwise unrelated phenotypic effects.

Codes only for a single discernible phenotypic effect.

Can be dominant or recessive.


Question 4

If an individual has inherited the same allele for a gene from both parents, they are said to be:








Question 5

Phenotype refers to:

The set of observable characteristics of an individual.

The morphology, behavior, and development of an individual.

The genetic makeup of an individual.

Both expressed and unexpressed genetic variation.


Question 6

Which of the following trait types can “breed true?” To “breed true” means that two organisms with a particular heritable phenotype produce only offspring with that same phenotype.

Recessive traits. (e.g. brown coloring, rough coats, tri-color, etc.)

Dominant traits. (e.g. black coloring, smooth coats, etc.)

Heterozygous Semi-Dominant traits. (e.g. Merle, Bobtail, Chinese Crested Hairless, German Shepherd Panda, etc.)

Heterozygous Co-Dominant traits. (e.g. AB blood type, red-white Roan in horses, etc.)


Question 7

What mode of inheritance do the following traits have in common: Merle, Bobtail, Harlequin, Panda (German Shepherds), Hairlessness (Xolo, Chinese Crested, etc.) ?

They are Lethal.  Lethal genes are capable of causing death.

They are all semi-dominant. When the heterozygote has a different, intermediate phenotype compared to the homozygous dominant or homozygous recessive individuals, it is said to be “semi-dominant.”

They are all recessive.

They are all dominant.

They are sex-linked.

They are all co-dominant.


Answers Here

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About Christopher

Christopher Landauer is a fifth generation Colorado native and second generation Border Collie enthusiast. Border Collies have been the Landauer family dogs since the 1960s and Christopher got his first one as a toddler. He began his own modest breeding program with the purchase of Dublin and Celeste in 2006 and currently shares his home with their children Mercury and Gemma as well. His interest in genetics began in AP Chemistry and AP Biology and was honed at Stanford University.