When I speak of the "earliest accounts I possess of my progenitors," authentic information is meant only; for, like other races, we have certain dark legends that might possibly carry us back again to the old world in quest of our estates and privileges.
The embarkation, or shipment of my progenitors, whichever may be the proper expression, occurred in the height of the last general war, and, for a novelty, it occurred in an English ship.
We may imagine that the early progenitor of the ostrich had habits like those of a bustard, and that as natural selection increased in successive generations the size and weight of its body, its legs were used more, and its wings less, until they became incapable of flight.
We may often falsely attribute to correlation of growth, structures which are common to whole groups of species, and which in truth are simply due to inheritance; for an ancient progenitor may have acquired through natural selection some one modification in structure, and, after thousands of generations, some other and independent modification; and these two modifications, having been transmitted to a whole group of descendants with diverse habits, would naturally be thought to be correlated in some necessary manner.
"Yet, might I presume to say so, the gem would make a rare sepulchral lamp, and would display the glories of your lordship's progenitors
more truly in the ancestral vault than in the castle hall."
As the purpose of this remarkable avenue dawned upon me I could not but admire the native shrewdness of the ancient progenitor
of the Mezops who hit upon this novel plan to throw his enemies from his track and delay or thwart them in their attempts to follow him to his deep-buried cities.
Silver et al., "Functional disruption of alpha4 integrin mobilizes bone marrow-derived endothelial progenitors
and augments ischemic neovascularization," The Journal of Experimental Medicine, vol.
Last May, his team had already revealed, in the journal Science, the temporal patterns governing the sequential birth of the different types of cortical neurons from progenitors
. 'This time, we looked at the potential plasticity of these progenitors
The higher concentration of luminal progenitors
, coupled with their maintained ability to form new tissue, helps explain why the prostate grows with age and why the risk of prostate cancer and benign prostatic hyperplasia increase: both are associated with the growth of cells.
The dynamic behavior of progenitors
during organ formation makes them difficult to study.
To examine how each progenitor
responded to its environment without the interference of other cells, he and his colleagues took progenitors
developed from human stem cells and seeded them onto glass slides that contained micropatterns of matrix proteins.