Hefzibah Eyal-Giladi (1925-2017): over fifty years of embryological research in Israel.

Hefzibah Eyal-Giladi was a creative and innovative pioneering scientist in the creation of the field of early chick embryo development. She had a sharp thinking and enthusiastic attitude, which enabled her to make a deep impression that was highly valued by the general scientific community. Notably, she was a highly successful female researcher in an era which was dominated by male scientists.

Evolutionary innovations of the vertebrates.

This review concentrates on the greatest anatomical and morphological evolutionary innovations of the vertebrates. During evolution, many new species of vertebrates evolved and underwent modifications by developing new forms, structures and functions of tissues and organ systems. Evolutionary development of the chordates and vertebrates is herein examined in terms of innovations in their organ systems and organismal complexity.

The importance of the posterior midline region for axis initiation at early stages of the avian embryo.

The avian blastoderm acts during its early stages of development as an integrative system programmed to form a single embryonic axis. Here, I report the results of a variety of transplantation experiments of the midline region at stages X-XII, which were carried out to study their relevance for axis initiation. The results of the experimental series discussed herein emphasizes the importance of the posterior midline region (including the marginal zone and Koller's sickle) for axis initiation.

Functional evolution in the ancestral lineage of vertebrates or when genomic complexity was wagging its morphological tail.

Early vertebrate evolution is characterized by a significant increase of organismal complexity over a relatively short time span. We present quantitative evidence for a high rate of increase in morphological complexity during early vertebrate evolution. Possible molecular evolutionary mechanisms that underlie this increase in complexity fall into a small number of categories, one of which is gene duplication and subsequent structural or regulatory neofunctionalization.

The evolution of genome size: what can be learned from anuran development?

Differences in nuclear DNA content in vertebrates have been shown to be correlated with cell size, cell division rate, and embryonic developmental rate. We compare seven species of anuran amphibians with a three-fold range of genome sizes. Parameters examined include the number and density of cells in a number of embryonic structures, and the change in cell number in the CNS during development.