Conceptual Answers to Ur Questions

This post was with reference to some questions posed by some students:

How does inbreeding result in a loss of genetic variation?
> i know that there is a collection of recessive alleles
> but isn't there crossing over to create variation?

Variation comes in all form. You are right to sasy that crossing over of non-sister chromatids of homologous chromosomes ensures variation but it is more significant at the individual level. Comparatively, there is a loss in the genetic variation because of the crossing over is done within a particular gene pool. No matter how you cross within a population, you are going to get only that few alleles (nelgecting mutation) for a gene. If you have cross/inter-breeding, you are open to more alleles and thus there is increased in genetic variation because the gene pool has expanded in quality.

-------------------------
How genetic uniformity would hamper the abiliy of species to adapt to ecological changes? (4)

> i know that there is little variation for natural
> selection to work on, but will it be extremely harmful or curb
> their chances of survival?

Yes because we are talking about the ability to survive into the next generation. So a change in environment can render the destruction of every individual in the population if there is no variation to increase the chances of survival for the species in the form of selected few who can continue the propagation of the species.

Thus I think as a guide you could have:
- genetic uniformity - no variation in population e.g. asexual reproduction which is conducive in a constant/stable environment
- But ecological changes e.g. environment/climate/predation can result in the destruction of every individual of a population if no variation exists.
- Because variation in a population will ensure that ..........
- thus the surviving few can reproduce and .........

-------------
To add to the post on Neutral Theory, do you know that when we talk about molecular homology we are examining the molecular homology of a particular amino acid sequeneces that give rise to a particular (conserved) protein e.g. mitochondria?