Cellular mechanisms explain differences in species biology

Researchers from the University of Eastern Finland and the University of Tampere have published a comprehensive study
in the journal Molecular Ecology on the significance of species differences for most central cell maintenance mechanisms.
The researchers used hares (Lepus europaeus) and snow hares (Lepus timidus) as model organisms
in their study.

The evolutionary lineage of hares (brown hares) and snow hares (mountain hares) separated about 3 million years ago
.
Mountain hares evolved in the Bering Strait region, and their close relatives lived in the Americas and the
Far East.
Mountain hares came to Europe very early and lived on the continent as early as the Ice Age
.
It still has an impressive continuous distribution from the Nordic countries to Far Eastern Russia
.
In contrast, the brown rabbit evolved in the Near or Caspian regions, while its modern relatives lived in Africa and the Near East
.

Due to their different evolutionary trajectories, the mountain rabbit is a species adapted to cold and snow, a coniferous and arctic species, while the brown rabbit is a milder, open jungle adapted species
.
In addition to habitat differences, the two species differ
in many other ways biologically.
Brown hares reach sexual maturity earlier than mountain hares and have a higher reproductive capacity
.
In contrast, mountain rabbits live longer, have a higher body temperature, and have poorer
access to nutrients than brown rabbits.
These differences evolved over millions of years of natural selection, resulting in genomic differences
.
Despite these differences, the two species interbred and produced fertile offspring
.
The study's authors were particularly interested in how these genomic differences translate into phenotypic differences in the most basic cellular functions, and whether these functional differences can explain the observed biological differences
.

When studying the cell lines of four brown hares and four mountain hares, the researchers noticed fundamental differences
in the regulation of several genomes.
Some of these genes cause brown rabbit cells to proliferate faster than mountain rabbit cells, which is related to
the way the species ages and matures.
Differences in cell proliferation can be further identified as differences
in cell cycle regulation.
There are also differences in energy metabolism and cell cycle regulation, indicating differences
in the resource input of the two plants to various characteristics of basic cellular functions.
The same differences in resource investment are likely to be reflected in
the ageing and reproduction of the two species.

The study helps to understand how genomic differences translate into adaptive phenotypic differences between species, how differences in life history strategies manifest themselves at the cellular level, and how species boundaries are formed
at the molecular level.
Some observations of hare cells have also been relevant
to understanding human ancestral hybridization, aging, and metabolic diseases.
The study also demonstrated that cultured cells could be used to study the ecological and physiological characteristics of wild animals, which reduces the need for
invasive sampling and animal experimentation.

Molecular phenotyping uncovers differences in basic housekeeping functions among closely related species of hares ( Lepus spp.
, Lagomorpha: Leporidae).