SLOTHS & BLUE GREEN ALGAE

Ever wonder why the slow moving sloth has a slightly greenish hue? Ever consider the sloth at all? Well, perhaps not. Location, location, location, is the mantra for many of us in our macro world, but it is also true for the small world of algae.

Blue green algae is a term used to describe any of a large, heterogeneous group of prokaryotic, principally photosynthetic organisms.

These little oxygenic (oxygen-producing) fellows appeared about 2,000,000,000 to 3,000,000,000 years ago and are given credit for greatly increasing the oxygen content of the atmosphere, making possible the development of aerobic (oxygen-using) organisms and some very special relationships with some of the slowest moving mammals on the planet, the sloths or Folivora.

The tribes of South America who live close to these insect and leaf-eaters, call these arboreal browsers "Ritto, Rit or Ridette, which roughly translates to variations on sleep, sleepy, munching and filthy. Not all that far off when you consider ths sloth and their lifestyle.

The sloth's body and shaggy coat, or pelage, provides a comfy habitat to two types of wee blue-green algae along with various other invertebrates. The hairs that make up the sloth's coat have grooves that help foster algal growth.

And, while Kermit the Frog says, "it's not easy being green," it couldn't be further from the truth for this slow-moving tree dweller. The blue-green algae gives the sloth a natural greenish camouflage, an arrangement that is certainly win-win.

AMYLASE: YOU ARE WHAT YOU EAT

The old adage, you are what you eat, might be best amended to you are what you can digest. 

For all the mammals, you and I included, we need the amylase gene (AMY). It codes for a starch-digesting enzyme needed to break down the vegetation we eat. 

Humans, dogs and mice have record numbers of the amylase gene. The AMY gene copy number increases in mammal populations where starch-based foods are more abundant. Think toast and jam versus raw chicken.

A good example of this is seen when we compare wolves living in the wild to dogs from agricultural societies. Dogs split off the lineage from wolves around 30,000–40,000 years ago. 

Domesticated dogs have extra copies of amylase and other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet, allowing Fido to make the most of those table scraps. Similar to humans, some dog breeds produce amylase in their saliva, a clear marker of a high starch diet. So do mice, rats, and pigs, as expected as they live in concert with humans. Curiously, so do some New World monkeys, boars, deer mice, woodrats, and giant African pouched rats. 

More like cats and less like other omnivores, dogs can only produce bile acid with taurine and they cannot produce vitamin D, which they obtain from animal flesh. Also, more like cats, dogs require arginine to maintain their nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.

The amount of AMY and starch in the diet varies among subspecies, and sometimes even amongst geographically distinct populations of the same species. I was at a talk recently given by Alaskan wolf researchers who shared that two individual packs of wolves separated by less than a kilometre ate vastly different diets. This had me thinking about what we eat and it is mostly driven by what is on offer. 

Diet impacts our genetics and this, in turn, allows the fittest to eat, digest and survive. While wolves win the carnivore contest, they will still eat opportunistically and that includes vegetation when other food is scarce. Would they evolve similar levels of AMY as humans, dogs and mice? Maybe if their diets evolved to be similar. Likely. The choice would be that or starvation.

The evolution of amylase in other domesticated or human commensal mammals remains an alluring area of inquiry.

Reference: 

Amylase in Dietary Food Preferences in Mammals: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516957/

YOU ARE WHAT YOU EAT... OR CAN DIGEST

The old adage, you are what you eat, might be best amended to you are what you can digest. 

For all the mammals, you and I included, we need the amylase gene (AMY). It codes for a starch-digesting enzyme needed to break down the vegetation we eat. 

Humans, dogs and mice have record numbers of the amylase gene. The AMY gene copy number increases in mammal populations where starch-based foods are more abundant. Think toast and jam versus raw chicken.

A good example of this is seen when we compare wolves living in the wild to dogs from agricultural societies. Dogs split off the lineage from wolves around 30,000–40,000 years ago. 

Domesticated dogs have extra copies of amylase and other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet, allowing Fido to make the most of those table scraps. Similar to humans, some dog breeds produce amylase in their saliva, a clear marker of a high starch diet. So do mice, rats, and pigs, as expected as they live in concert with humans. Curiously, so do some New World monkeys, boars, deer mice, woodrats, and giant African pouched rats. 

More like cats and less like other omnivores, dogs can only produce bile acid with taurine and they cannot produce vitamin D, which they obtain from animal flesh. Also, more like cats, dogs require arginine to maintain their nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.

The amount of AMY and starch in the diet varies among subspecies, and sometimes even amongst geographically distinct populations of the same species. I was at a talk recently given by Alaskan wolf researchers who shared that two individual packs of wolves separated by less than a kilometre ate vastly different diets. This had me thinking about what we eat and it is mostly driven by what is on offer. 

Diet impacts our genetics and this, in turn, allows the fittest to eat, digest and survive. While wolves win the carnivore contest, they will still eat opportunistically and that includes vegetation when other food is scarce. Would they evolve similar levels of AMY as humans, dogs and mice? Maybe if their diets evolved to be similar. Likely. The choice would be that or starvation.

The evolution of amylase in other domesticated or human commensal mammals remains an alluring area of inquiry.

Reference: 

Amylase in Dietary Food Preferences in Mammals: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516957/