I knew it! A clone army.

I found this article. Read it. A clone army... of clams.

This is a very special case where an organism clones itself using parts normally used for sexual reproduction. This clam has both male and female parts (a hermaphrodite). The clam fertilizes its own egg with its own sperm. Now if this were it, the clam would simply be self-fertilizing, similar to some flowering plants. The mix of genes from egg and sperm would be producing different combinations of genes in the offspring. In other words, they would not be clones.

To get around this, the clam ejects the eggs genes. So now we have the sperms genes only in this fertilized egg. Only sperm genes get passed on. This cuts down the variety of genes, but is still not producing genetically identical clones. When sperm are made, there is genetic recombination that goes on in the process. This creates combinations that make each sperm genetically unique. Is this genetic recombination happening in these clams?

Another way that these clams get new gene combinations is by capturing genes from other species of clam. The process requires the clam to first fertilize another species' egg (no barriers against this?) and then eject the other species' genes. Sometimes, however, some of the genes are thought to be kept and integrated into the clam genome. New genes, hurray!

I have two questions about this clam and will give extra credit if anyone can find the answer:

1. What is happening during meiosis when this clam makes sperm, is there genetic recombination (crossing-over)?

2. How does the clam deal with the problem of conserving (keeping) the same number of chromosomes (haploid sperm to diploid zygote) if they are getting rid of the egg genes every time?

Happy Hunting!

Convergent evolution

Lizard fossil provides missing link to show body shapes of snakes and limbless lizards evolved independently

We have talked about convergent evolution and here is another example. There are snakes and then there are legless lizards. Some thought they were closely related since they are both legless, but this new evidence shows that having no legs has evolved in these two groups independently. How can this occur? How is this an example of convergent evolution?

What is to thank for the evolution of the mammal brain? Thank the fact that you smell!

We've been talking a lot about evolution and there has been a little discussion as to brain evolution. New research has been done to show that mammal brains probably evolved for better smelling ability. They say that the smell centers of the brain evolved first. So, feel good about the fact that you all smell and that the history of you smelling (in your distant evolutionary past) has allowed for your well-evolved brain!

Earliest mammals sniffed their way to smarts