My father died when I was a boy. He was a good man, but I simply can’t remember too many things about him. This is because he was a very hardworking man – a workaholic. That is why I do not have many memories of him.

Thanks to Dad, I too am a workaholic. But long ago, I made a promise to myself that I would make time, lots of time, for my own children. I would give them the advice, memories and experiences that I do not have. But for some time now, that promise has been stretched beyond the breaking point and I can no longer ignore it or rationalize ignoring it. I can’t continue with my selfishness.

Over the years, I have informed readers that my involvement with these issues of teleology and life have been a hobby, practiced on the internet. It’s fun, intellectually stimulating, and very interesting. But since time and energy are limited, what this has meant is I have had to choose between my involvement with these issues and my involvement with my family. I used to get around that choice by sacrificing sleep, but the body has taken that choice away.

What this all means is that since my involvement with this blog has been the major ingredient in my involvement with these issues, this is my last posting to Telic Thoughts, as I am retiring from this blog. I have promised my family to spend much less time on the internet and, for me, ‘internet’ essentially means this blog. I’ll still post substantive material once or twice a month over at the book blog, but this is the place that has obviously consumed most of my time. Too much time.

I have truly enjoyed my experiences with the people here, so there is a real sense of sadness when leaving. You are a unique set of individuals, with interesting perspectives and, more often than not, thought provoking positions and questions. I’ve enjoyed the humor, the links, the arguments, the passion, the challenges, and yes, even the fights. I don’t know of any other place that can substitute for this corner and the folks who are here, my fellow contributors and those who regularly comment. I will miss it. And you.

Some of you may be disappointed with my decision, others may not care, while yet others may be gleeful. Some may try to read between the lines, thinking there are other forces at work. Yet the only force at work here is my father, my promise, and my family. I’d like to believe that my father would smile at this decision, saying, “Good job, son.”

But I can't say for sure.

And I want my children to be able to say for sure.

So, from the bottom of my heart, I thank you all and wish you only the best. Farewell.

This is a long article, but worth the time to read it:

The tragic view comes closest to describing how I now look at Peter Singer. He is a man of unusual gifts, reaching for the heights. He writes that he is trying to create a system of ethics derived from fact and reason, that largely throws off the perspectives of religion, place, family, tribe, community and maybe even species — to "take the point of view of the universe." His is a grand, heroic undertaking.

But like the protagonist in a classical drama, Singer has his flaw. It is his unexamined assumption that disabled people are inherently "worse off," that we ''suffer," that we have lesser "prospects of a happy life." Because of this all-too-common prejudice, and his rare courage in taking it to its logical conclusion, catastrophe looms. Here in the midpoint of the play, I can't look at him without fellow-feeling.

Hydra vulgaris is a member of the phylum Cnidaria. It appears to be a relatively simple animal and has a small number of cell types (you can read more about its basic biology here). Yet, as we have seen, it turns out that cnidarians actually possess a rather complex genetic tool kit.

We have also seen that receptor tyrosine kinases (RTK) would play important roles in facilitating the evolution of multicellular life. Added to this is the recent discovery that one example of an RTK, the insulin receptor, plays an important role, along with its ligand insulin, in the development of the nervous system.

So let’s begin the process of tying this together.

Could it be possible that the protein hormone insulin, that is spread throughout the body of mammals via the circulatory system, would actually play a role in the development or life of Hydra? In 1996, Steele et al. (1) identified a gene for a receptor tyrosine kinase that was very similar to the insulin receptor in mammals, called HTK7. They found that is was expressed in ectodermal cells (the cell type that can generate nervous tissue) at both ends of Hydra’s tube.

But what is most striking of all is that they found insulin, obtained from cows, had the ability to induce both DNA replication and cell division in Hydra’s ectodermal cells.

Okay, from the perspective, there is nothing all that surprising about finding insulin receptors, and responsiveness to mammalian insulin, in cnidarians. This is just another example of deep homology that is consistent with such a system being in place with the last common ancestor of all animals.

What’s more interesting this time around is that we are talking about a hormone and its receptor. Here, the function is simple - BIND. What makes this interesting is that cows and Hydra last shared a common ancestor at least 600 million years ago. This in turn means there are 1.2 billion years of evolution that separate the Hydra insulin receptor and the bovine insulin.

Each lineage would possess an independent history of mutations in the receptor followed by secondary, suppressor mutations in the ligand. Each lineage would possess an independent history of mutations in the ligand followed by secondary, suppressor mutations in the receptor. Yet despite two separate spans of co-evolution between receptor and ligand, the ligand from cows retains the ability to function with the receptor from Hydra.

All that this indicates a fairly strong selective constraint on a seemingly simply biochemical function (BIND). So where do we go from here?

1. R. E. Steele, Pauline Lieu, Ninh H. Mai, M. Andrew Shenk and Michael P. Sarras Jr. 1996. Response to insulin and the expression pattern of a gene encoding an insulin receptor homologue suggest a role for an insulin-like molecule in regulating growth and patterning in Hydra Development Genes and Evolution 206:247-259

"Hey Mike, why don't you just drop that ID label once and for all and come up with something new. That way there would be less confusion!"

Yeah, and what might many of the critics see if I took their friendly, helpful advice?

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By analyzing the recently-sequenced choanoflagellate genome, the researchers discovered another similarity between choanoflagellates and most metazoans–their genetic code caries the markers of three types of molecules that cells use to achieve phospho-tyrosine signaling proteins.

Animals depend on tyrosine phosphorylation to conduct a number of important communications between their cells, including immune system responses, hormone system stimulation and other crucial functions. These phospho-tyrosine signaling pathways utilize a three-part system of molecular components to make these communications possible.

Tyrosine kinases (TyrK) 'write' messages between cells by adding phospho-tyrosine modifications, protein tyrosine phosphatases (PTP) are molecules that modify or 'erase' these modifications, and Src Homolgy 2 (SH2) molecules 'read' these modifications so the recipient cell gets the message.

Without these three molecules to help our cells 'write,' 'read' and 'erase' chemical messages between them, our bodies would never be able to conduct the complex tasks needed to survive such as reproduction, digesting food or even breathing.

Other genome analysis showed that some microorganisms contain some of these molecules in small levels, but never all three. This makes sense considering these organisms don't need the tools to communicate between cells since they are made up of only one cell. What makes choanoflagellates unique, however, is that they have all three of these molecules. What's more, they have relatively large quantities of them in amounts commonly seen in larger metazoan organisms.

The researchers conclude that the presence of the full three-component signaling system may have played a role in the development of metazoan organisms whose cells could communicate with each other in complex ways.

Here

HT: fifth monarchy man

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Spain’s Parliament has voiced its support “for the rights of great apes to life and freedom.” Yet this bold and historical decision to extend human rights to apes is plagued with arbitrary thinking.

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He obeys my every command.