As the adage goes, you can pick your friends, but you can’t pick your relatives. This even applies to your distant evolutionary cousins. In terms of a very specific genetic function, humans are a little bit more closely related to the sea lamprey than scientists once believed. According to a study published February 20 in the journal Nature Communications, we share similar hindbrains as these 500-million-year-old animals with suction-cup mouths and sharp teeth.
[Related: Giant prehistoric lamprey likely sucked blood—and ate flesh.]
What is the hindbrain?
There are three basic units of an vertebrate brain–the midbrain, forebrain, and the hindbrain. According to the National Institutes of Health, the hindbrain includes the upper part of the spinal cord, the brain stem, and the cerebellum. It controls some of the vital functions that are necessary to our survival, including blood pressure, heart rate, respiratory rhythm, motor activity, sleep, and wakefulness.
The hindbrain is an older region that has been evolutionarily conserved, or virtually unchanged throughout the process of evolution. Studying it can help evolutionary biologists peer back into the past and put together timelines for brain development and other physical features.
Sea lampreys are fish native to the Atlantic Ocean and Great Lakes. They spend about 12 to 18 months in a parasitic stage where they suck on other fish to live, before they detach. They have remained unchanged for the last 340 million years, but have a backbone and skeleton like other vertebrates. However, they are missing a jaw on their heads. Since most vertebrates have jaws, this difference in sea lampreys makes them crucial for understanding vertebrate evolution.
“There was a split at the origin of vertebrates between jawless and…
Read the full article here