Chimeras and meristems

I-18: Avian Chimeras and Germ Cell Migration

Background: In avian species, the germ line stem cell population arises outside of the embryonic gonad and proceeds on a circuitous migration to the germinal epithelium. Specifically, in the avian embryo, the process of germ line stem cell migration proceeds through a series of active and passive migratory phases. The germline stem cells or primordial germ cells (PGCs) located in the epiblast o...

Behavior of Leaf Meristems and Their Modification

A major source of diversity in flowering plant form is the extensive variability of leaf shape and size. Leaf formation is initiated by recruitment of a handful of cells flanking the shoot apical meristem (SAM) to develop into a complex three-dimensional structure. Leaf organogenesis depends on activities of several distinct meristems that are established and spatiotemporally differentiated aft...

Mouse-chick neural chimeras.

Embryonic chimera production was used to study the developmental processes of the mouse nervous system. The difficulty of performing in situ transplantation experiments of neural primordium of mouse embryo was overcome by isotopic and isochronic grafting of mouse neural tube fragments into chick embryo. Mouse neural tube cells differentiated perfectly in ovo and neural crest cells associated wi...

Chimeras of nurture.

Timing of nucleolar activity in meristems.

The nucleoli in 4 regions of the root meristem of Zea mays have been examined and the time spent in each of the phases of the nucleolar cycle has been calculated from estimates of the rates of mitosis and the fraction of cycling cells in each region. The nucleolar cycles have been fitted to the mitotic cycles of cycling cells in the same regions. The timing of activity of the r-RNA genes differ...