Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Emus emulate chick developmental stages

18.02.2011
Birds are useful models in developmental biology, but the study of avian development has been dominated by a single species of chicken. New research provides a comparative description of the development of the emu with that of the better-known chick.

Birds are useful models in developmental biology, given their large, external eggs and an array of classic embryology techniques, but the study of avian development has been dominated by a single species, the chicken Gallus gallus.


The emu, Dromaius novaehollandiae(left), and a comparison of emu and chicken eggs (right)

While a few other bird varieties have been studied for purposes of comparison, these have all been from the “modern” species (neognaths), such as quail, duck and pheasant. A number of more basal bird species (palaeognaths), including ostrich, rhea, kiwi, and emu survive, but their development has remained unstudied.

Now, in a report published in Developmental Dynamics, Hiroki Nagai of the Laboratory of Early Embryogenesis (Guojun Sheng, Team Leader) and colleagues from the same lab as well as the Laboratory for Sensory Development (Raj Ladher, Team Leader) provide a comparative description of the development of the emu, Dromaius novaehollandiae, with that of the better-known chick. The team found that while the two birds’ proceed through similar embryonic stages, a number of differences in timing and pace set them on the widely diverging courses manifested in their adult forms.

Nagai’s approach centered on identifying emu equivalents for Hamilton-Hamburger stages in the chick. The Hamburger-Hamilton (HH) system uses definitive morphological characteristics to determine the state of development, and is the gold standard in staging chick embryos. As a general rule, emus take 2–3 times longer than chicks to reach the same HH stage.

The early development of the emu resembles that of the chick until HH7. During subsequent stages in which somites form, however, the emu forms a greater number of these structures than the chick. The emu somitogenic period was calculated to be 100–110 min, slightly longer than the 90 minutes in chick embryos.

The forelimbs in adult emus are diminutive, which is reflected in development as well. The forelimb buds form and undergo initial patterning, but these appendages fail to grow apace with the rest of the embryo body, including the hindlimbs. Interestingly, adult emus also have fewer forelimb digits than do other birds, a difference that is also observable at the stage of the limb’s patterning. Once the limb buds have formed, the emu embryo begins a growth spurt that results in the enormous size differential with the chick.

In addition to their comprehensive morphological observations, the team looked at the expression of a number of genes, such as Sonic hedgehog (Shh), Brachyury, and Chordin, known to be important in early development. Expression patterns were similar to those in chick up to stage 7, when the first somite appears, with the single exception that the Brachyury expression begins slightly later in emu.

“Since a brief description by Haswell in 1887, there has not been any published study of emu development,” says Sheng. “In staging these embryos, we learned of the high level of conservation of developmental routines across bird orders, which suggests that findings from the chick may well apply generally to birds. That said, we also saw heterochrony in the development of specific tissues and structures between chick and emu, so we look forward to studying these embryos in more detail through cell labeling, transplants, and imaging techniques.”

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

20.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>