Update for the Genetics: Linked Genes and Meiotic Recombination

[Robb Plat]

More, diverse genes are needed. Currently we have Autosomal and X-linked dominant and recessive alleles. We have fully dominant, and incompletely dominant genes.

 

Linked genes far more accurately describe genetics. At the moment, it seems like our Nichelings have many autosomes that are on separate chromosomes. Unlike Mendel's Peas, however, it is unlikely that a mammal would have all these genes without a few of them being on the same chromosome. Also it adds a touch of difficulty and intrigue, not to mention it's an concept of importance in genetics.

We need linked genes (two alleles that are inherited together), and crossing over, which  occassionally occurs with linked genes. (The two alleles that are inherited are not the same as the one inherited from the grandparent. The alleles have switched. Example below.)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

An example to illustrate for my idea (which is merged with an idea for the wings update):

 

Wings = w

No Wings = W

Feathers = f

No feathers = F

capital letter alleles are dominant, and lower case alleles are recessive.

 

P: FW/FW x fw/fw = F1: FW/fw

(No wings, no feathers parent bred with feathered and winged parent produces non-winged, non-feathered F1 offspring

(x means bred with)

F1: FW/fw

F1 x F1 (F1 dihybrid cross) = FW/fw x FW/fw

if these linked genes are very close to each other on the chromosome, then crossing over in meiosis is unlikely, and all offspring are either FW/FW, FW/fw, or fw/fw

2 non-winged, non-feathered: 1 winged and feathered offspring.

 

However assuming that there is a small chance of crossing over (just set it at a small probability, like 25% = 25 m.u.) then you get the following idea percentages:

FW/fw (F1) x fw/fw (This is a dihybrid testcross):

F2:

37.5% FW/fw = 3/8 of offspring are non-winged, non-feathered (like a terrestrial animal)

37.5% fw/fw = 3/8 of offspring are winged and feathered. (like a bird)

12.5% Fw/fw = 1/8 of offspring are winged but not feathered (like bats wings)

12.5% fW/fw = 1/8 are feathered, but don't have wings/wings are too small to fly? (like a dodo or kiwi bird< very small wings>)

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Phylogenetic recap:

P: FW/FW x fw/fw

F1: FW/fw

 

F1 testcross: FW/fw x fw/fw

F2 (for 25%): 3 FW/fw: 1 Fw/fw: 1 fW/fw: 3 fw/fw

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

(n.b.:  I might have gotten the numbers wrong, I would appreciate any corrections if I made any mistakes.)

It seems complicated, but the main idea when these two genes (feathers and wings) are present in a heterozygote, there is a possibility that the genes will not be inherited together. For added difficulty, this would be an amusing and exciting challenge.

Naturally an achievement would come up saying "Meiotic Crossing-Over".

Three linked genes would also work/be interesting.