codominant or dominant spiders

[bigballs]

so the spider characteristic is considered dominant because there is no super form of the spider morph. in reality the spider gene is a codominant one because the theoretical clutch odds of a spiderXnormal pairing is 50% spiders and 50% normals.

when breeding a spiderXpastel the odds for a bumblebee to pop out are exactly the same odds as pairing a pastelXpastel and hoping for a super pastel to pop out. which are the same odds as breeding a pair of 100% het animals and having a 25% chance at hatching out the homozygous form of the bred hets.

so by breeding a pastel to spider i have a 25% chance at hatching out a bumblebee right?

[Wh00h0069]

so the spider characteristic is considered dominant because there is no super form of the spider morph. in reality the spider gene is a codominant one because the theoretical clutch odds of a spiderXnormal pairing is 50% spiders and 50% normals.

when breeding a spiderXpastel the odds for a bumblebee to pop out are exactly the same odds as pairing a pastelXpastel and hoping for a super pastel to pop out. which are the same odds as breeding a pair of 100% het animals and having a 25% chance at hatching out the homozygous form of the bred hets.

so by breeding a pastel to spider i have a 25% chance at hatching out a bumblebee right?

Each egg has a 1/4 chance of being a bumblebee, and 1/4 chance of being a spider, a 1/4 chance of being a pastel, and a 1/4 chance of being a normal.

[bigballs]

Each egg has a 1/4 chance of being a bumblebee, and 1/4 chance of being a spider, a 1/4 chance of being a pastel, and a 1/4 chance of being a normal.

so in a pastelXpastel pairing you get 25%normal, 50%pastel, and 25% super pastel. these odds are pretty much the same as a pastelXspider except that instead of the 50% pastel, you get 25% pastel and 25% spider because of the spider gene and 25% normal and 25% bumblebee.

[Freakie_frog]

Well we call spiders Dominate because there is no "super" form but that doesn't mean that their can be a Homozygous form which means its Co-dominate we just call it Dominate to keep the genetics simple.

[littleindiangirl]

It's dominant in the sense that it only takes one copy of the gene to pass along the full expression of the phenotype of the gene instead of the two genes like a pastel or a recessive trait.

[bigballs]

It's dominant in the sense that it only takes one copy of the gene to pass along the full expression of the phenotype of the gene instead of the two genes like a pastel or a recessive trait.

so because the spider phenotype is fully expressed after only one breeding, the phenotype or spider characteristic is considered dominant. the genotype of the spider however, is codominant, so calling the spider characteristic dominant is only a way of saying there is no further expression of this phenotype.

so the genotype and phenotype of a pastel is codominant, then that of a super pastel is dominant?

[littleindiangirl]

Very very very close. You have it just about correct.

so because the spider phenotype is fully expressed after only one breeding, the phenotype or spider characteristic is considered dominant.

I get what your saying in the whole, but the terminology is off. Since the spider gene is fully expressed when heterozygous (only one copy), then it is considered dominant.

the genotype of the spider however, is codominant, so calling the spider characteristic dominant is only a way of saying there is no further expression of this phenotype.

I'm not sure if we could consider the gene co-dominant or incomplete, or just dominant in reference to terminology. I have never understood why people consider it just a dominant. Maybe someone wants to step up to the plate and explain that one.

Generally speaking, if you were in a biology class, co-dominant and incomplete dominant means something different than what we think of in our everyday hobbyist lingo.

http://www.emc.maricopa.edu/faculty/...ninteract.html

Codominant alleles

Codominant alleles occur when rather than expressing an intermediate phenotype, the heterozygotes express both homozygous phenotypes. An example is in human ABO blood types, the heterozygote AB type manufactures antibodies to both A and B types. Blood Type A people manufacture only anti-B antibodies, while type B people make only anti-A antibodies. Codominant alleles are both expressed. Heterozygotes for codominant alleles fully express both alleles. Blood type AB individuals produce both A and B antigens. Since neither A nor B is dominant over the other and they are both dominant over O they are said to be codominant.

(or a red and white flower when crossed will give a red and white spotted flower because both colors are dominant)

Incomplete dominance

Incomplete dominance is a condition when neither allele is dominant over the other. The condition is recognized by the heterozygotes expressing an intermediate phenotype relative to the parental phenotypes. If a red flowered plant is crossed with a white flowered one, the progeny will all be pink. When pink is crossed with pink, the progeny are 1 red, 2 pink, and 1 white.

[littleindiangirl]

so the genotype and phenotype of a pastel is codominant, then that of a super pastel is dominant?

Two different ideas here, but also, very close.

Since the super pastel has two copies of the pastel gene, each animal that it sires will receive one copy of the pastel gene from them, making them pastels.

The pastel gene is still incomplete dominant, whether the animal has one or two copies of the gene. That is just the way the gene works. The pastel, which only carries one copy of the gene, is only showing a partial expression of the pastel gene. The pastel has only one pastel gene to pass along, so some of the babies get the normal gene, and some get the pastel gene.

When that pastel has both copies, they show the full expression of the gene, the Super pastel. It is still an incomplete dominant, but the super has 2 pastel genes to pass along instead of just one.

I think your getting methods of inheritance crossed with the way the genes work by themselves.

[Freakie_frog]

Correct but its not dominate in the fact that it still produces the wild type offspring so in a since its not. A true Dominate gene would have no super and not produce any normal offspring.

[littleindiangirl]

Correct but its not dominate in the fact that it still produces the wild type offspring so in a since its not. A true Dominate gene would have no super and not produce any normal offspring.

Ed, that's not correct. Spider is a dominant gene. It truly is, however most spiders are hets, and they do not pass all spiders because of the way genes are inherited.

If each animal receives one copy of a gene from the parents, using the heterozygous spider as an example, what guarantees that this "dominant" gene is the one that gets passed along to the offspring and not the normal gene?

A gene can be dominant, but that in no way means that there will be no normal offspring unless the animal is homozygous for that gene.