Gene families and evolution?

Question

I answered this question for homework and got only a 6 out of 10 and I'm having a problem. If someone could please help me, I would greatly appreciate it!

A. Define the term gene family; give an example

B. Describe a mechanism that creates a gene family.

C. What is the implication of gene families for evolution?

Here is what I talked about and it was wrong...Shared alleles within a group. I spoke about a gene family being created by a crossover allowing for the mixing of dominant and recessive traits.

Answer 1

Mistake #1.  An allele is a variant of a single gene.  A single gene has many alleles.  Evolution is defined as the change in the frequency of alleles in a population over time.  Depending on the allele, it can act as a dominant or recessive variant.  

Gene family means a group of related genes (not alleles).  For example, there are many related proteins called hemoglobins.  Hemoglobin alpha, beta, gamma, delta, epsilon....  They have similar amino acid and nucleotide sequence (which is why they are grouped together into a family).

Mistake #2.  Gene families are created by gene duplication.  Look up how the ancestral gene myoglobin got duplicated and created the hemoglobin family.  

Crossing over results in recombination or a reshuffling of DNA between homologous chromosomes.  Crossing over creates new combination of alleles, not new genes.

As for question C, having an extra copy of a gene means that evolution can happen at a faster rate.  More mutations/variations can be allowed because even if mutations kill the function of one gene, there's another backup copy.  More mutations means that a gene product can acquire different functions and at a faster rate.

Answer 2

Just make something up.  They do it all the time on TV and in books.

Just use the Evolution formula:

something happened

a lot of time passed

something else happened

Make up anything you want, just apply the formula and no one will question your conclusion.

How could they, how could it be disproved?

As in "The King Has No Clothes", anyone caught questioning Evolution will be punished.

And as in "The Wizard of Oz", do not look behind the curtain: In over 100 years the missing link has not been found.

Answer 3

Perhaps it would be better to talk to your instructor, rather than a bunch of anonymous strangers?