How many blue lobsters does it take to start a business?

Uncommon Descent, for some reason, just posted a link to an article about a blue lobster. This isn't the first time that a blue lobster has been found, and there are even rarer yellow and albino variants that are known. Since there is, as the UD article points out, a trade in blue crayfish, it's reasonable to assume that the blue coloration in lobsters is a heritable. All that leaves me wondering something: exactly why did the folks at Uncommon Descent decide to highlight this example?

The UD article contains the following gem:

Apparently, there is a trade in blue crayfish for aquariums, but any similar trade on blue lobsters depends on finding another one, of the opposite sex.

Does it really?

I didn't take a lot of time to research the genetic mechanisms underpinning lobster coloration (frankly, it's not a topic that fascinates me). I did find, however, that there's reason to suspect that the blue coloration is the result of a recessive trait (a paper I found noted that a prior study had found that blue offspring only occur when two blue lobsters mate). If that's the case, does a would-be purveyor of blue lobsters really need two blue lobsters to get the business off the ground?

The answer to that question, of course, is no. That's really, really, really simple genetics. It's middle school science. If that. I made my daughter work the problem and she complained that she was having a hard time because she had to dig way back to remember how to do those problems. She's just finishing 8th grade.

If you have one fertile blue lobster, one fertile normally-colored lobster, time, and patience, you will eventually be able to start your business. The first generation of offspring will be carriers. Breed them, and you can expect that ~25% of the second generation will be blue. Breed only those blue ones, and you're off to the races.

Punnett squares are your friends, when the genetics are simple.

There is no requirement that a new mutation simultaneously appear in two individuals of the opposite sex if the mutation is to spread through the population.

18 responses so far

  • Frank B says:

    Wouldn't you have a problem from inbreeding? All your stock is from one breeding pair of lobsters. You could mitigate that somewhat by having your blue lobster mate with (say) ten normal lobsters of the opposite gender. Then you would have a variety of step siblings that were all carriers.

  • sparc says:

    If lobsters had ribs it would be easy to create the second sex. Relevant literature is readily available in nightstand drawers in any US hotel room.

  • sparc says:

    I guess the UD poster thinks that this is an example showing why speciation could not happen. For her/him the blue lobster is a hopeless monster sitting in a reproductive dead end street.
    BTW, the money shot is this:

    Mutation explained here.

    linking to the Globe and Mail article which says:

    Just one lobster out of millions is blue, the result of a genetic mutation that causes a protein to bind to the crustacean’s pigment and change its colour.

    Isn't this exactly the kind of irreducible complexity ID-creationists always claim cannot arise without the intervention of an intelligent designer?

  • becca says:

    And a *lot* of patience. Lobsters take 1.5-2 years from impregnation to babylobster hatching and perhaps 5 years to sexual maturity*. So you're talking 8-9 years just to get your blue. It might actually be faster to go look for another mutant freak. In fact, if the lobster really was '1 in a million', since national geographic informs me that worldwide 200,000 tons of lobster are caught every year, if we assume (conservatively, for # of lobsters) each lobster weighs 5 lbs, then there should be 80 blues per year.

    *(I may be mixing different numbers from different species, this is the result of a very cursory consultation with Teh Google, so this could be wrong-anyone who knows anything about lobsters is invited to educate me here).

  • Bob O'H says:

    All that leaves me wondering something: exactly why did the folks at Uncommon Descent decide to highlight this example?

    "News" is Denyse, so how exactly does this article by her differ from any other?

  • Eamon Knight says:

    @Bob O'H: "News" is Denyse, so how exactly does this article by her differ from any other?

    Ah, that explains it.

  • I think that Denyse O'Leary has some sort of notion that she's an actual science blogger so links to science issues she finds interesting even when they aren't directly connected to ID. At some level that's a positive compared to the other UD people who only are interested in science when it can be used in the service of ID.

  • Lou Jost says:

    I am not defending the wingnuts, but do we really know that this is caused by a single mutation? If it requires mutations at several bases, and if these are not too tightly linked, it may be really improbable to get a blue offspring in the second generation after outcrossing. This seems to be the case with some blue mutant orchids, for example.
    Lou

  • John vreeland says:

    "At some level that's a positive compared to the other UD people who only are interested in science when it can be used in the service of ID."

    When does this happen?

  • jswise says:

    I believe there's a blue lobster at the Seacoast Science Center in Rye, New Hampshire, USA. Maybe they'll eventually have an aquarium full of blue lobsters.

    Frank B, I think inbreeding and its associated problems are common among domestic plants and animals. A recent guest on Fresh Air talked about how incestuous show dogs are. He said English bulldogs can't even give birth except by Caesarian. You might say they turn the idea of a species on its head, since they can't really mate with their own kind.

    • truthspeaker says:

      The thing with English bulldogs is because of the size and shape of their heads, not inbreeding directly. They were bred for that head size, and inbreeding was probably involved.

    • Mokele says:

      You should see albino boas. There are two "lines", each of which are descended from a single individual via sibling and parent-offspring inbreeding. The result, in less than 10 generations, is snakes routinely born missing one or both eyes (either covered with skin or just an open socket).

      There are plenty more reptile "morphs" due to simple recessive traits, thus propagated by inbreeding, and many lineages display failed righting responses, inner-ear problems resulting in "spinning" behavior, kinked spines, malformed jaws, missing eyes, partial or complete lack of scales, and dramatically reduced lifespans (in one case, 90% reduction). This, of course, ignores the plentiful internal anomalies which are likely present but are missed due to lack of systematic reporting of necropsies.

      Of course, tell any of them this, and they'll assert that by "outcrossing" for a single generation (thus cousin-cousin inbreeding), all of this will magically vanish, rather than just happening more slowly.

  • snaxalotl says:

    "a prior study had found that blue offspring only occur when two blue lobsters mate"

    this is inconsistent with what you are arguing. also, you don't seem to have established that blue color is the result of a single gene

  • Jim Thomerson says:

    I recall reading, but could not give you a reference, that blue crayfish was due to a recessive gene, and was inherited in a Mendelian manner. Blue crayfish showed up in the aquarium trade a fairly short time after there was an article about someone finding a blue crayfish. I may have caught one in the wild one time, but don't trust my memory of the event.

  • CG says:

    "this is inconsistent with what you are arguing. also, you don't seem to have established that blue color is the result of a single gene"

    No, it's not. If the blue gene is recessive, two blue lobsters is the only way to have 100% chance you would get blue offspring.

    If it really is that rare, randomly getting two carriers is be improbable.

  • Jim Thomerson says:

    Actually you need only one carrier. If frequency of homozygous blue individuals is one in a million, my Hardy-Weinberg calculations (which may be suspect) suggest heterozygous are about 1 per 500. So if one has an easy, rapid, nonlethal test for the blue gene, finding a heterozygous mate who should give half homozygous blue offspring is not that difficult.

  • Riley says:

    I'd say that the Blue color is by far the most unnatural looking. I can see why they would highlight it.