Biology II: Mouse, Zebrafish, and Chick

Laboratory mice are important research animals for studying human disease progression and development. Mus musculus is small, but it shares strong genetic similarity with humans. Mice also reproduce and mature quickly. These traits make them efficient and economical mammals for scientific study.

The video also introduces common laboratory mouse strains. One example is the nude mouse. Its genetic makeup makes it hairless and immunodeficient, which means it has a weak immune system. These strain...

Chicken embryos are important model organisms in developmental biology. Most of their development happens inside an egg outside the mother. That makes early stages easy to access, observe, and manipulate through a small opening in the eggshell.

Chickens are also practical for research. Billions are raised worldwide for meat and egg production, so fertilized eggs are easy and inexpensive to obtain throughout the year. Chickens also share strong genetic conservation with humans, so genetic...

Zebrafish, or Danio rerio, are small freshwater fish used in biomedical research. They are important model organisms because they share a high degree of genetic conservation with humans. They are also simple and inexpensive to maintain in the lab.

Zebrafish embryos are especially useful because gene expression can be easily manipulated. Their transparency makes it possible to observe developmental processes directly. The video also introduces basic zebrafish biology, including their phylogeny,...

Mouse housing, handling, and injections are key parts of laboratory animal care. Mice are small rodents that breed and reach sexual maturity quickly. That makes them useful for building large animal colonies for biological research. They are also simple and inexpensive to maintain in the laboratory.

Mouse colonies still need careful husbandry. Husbandry means the routine care needed to keep animals healthy and safe. These needs also help support experimental reproducibility. The video focuses...

Chicken eggs and chicks are useful in research on vertebrate development, neuroscience, tumor biology, and virus growth. They are also practical to work with because eggs can be bought from outside suppliers and the setup needs very little special equipment. Even so, normal embryo development depends on proper handling.

Careful incubation is a key part of chick work. The main conditions are temperature, humidity, and egg rotation, and each one can strongly affect development. The video...

Zebrafish lab care focuses on keeping Danio rerio healthy in a research setting. These small vertebrates are used to study development, model disease, and screen for new therapeutics. Their size also lets labs house many fish at low cost.

Good zebrafish health depends on diet and water quality. The lab environment should match key parts of their natural habitat as closely as possible. That includes a fish facility water recirculation system that helps keep the water conditions stable.

Feeding...

Mouse breeding, sexing, and development stages are key parts of maintaining a healthy laboratory colony. The laboratory mouse, Mus musculus, is widely used in research because its growth and reproduction can be studied closely. Scientists also use mouse embryos to learn about development and heritable diseases that affect human growth.

Mouse development begins before birth and continues after birth as pups grow. The earliest rodent embryos have a unique layout, and the presentation reviews the...

The chicken embryo is a useful model for studying early development. It is economical and easy to access, which makes it practical for developmental biology research. Chick embryos also develop quickly and can be used in genetic and physiological studies at the cell and molecular levels.

Development begins with egg fertilization and the formation of the egg within the chicken reproductive tract. The chick is then followed using the Hamburger Hamilton staging series, which is the most common...

Zebrafish development moves quickly through the first 24 hours after fertilization. The early embryo is transparent, which makes it easy to see tissue changes and cell movement under the microscope. Zebrafish are also useful in genetics because researchers can change gene expression and watch how it affects a vertebrate that is genetically similar to humans.

Development begins with a zygote, a single cell called a blastomere, sitting on top of a large yolk ball. Cleavage then divides that cell...

Mouse DNA tracking helps scientists follow inherited traits across generations. Because mice share a high degree of genetic similarity with humans, they are a common model for studying how genes affect biology. Researchers often change a gene sequence and then look for the phenotype, or visible effect of that change, in the animal.

To keep track of mice with these genetic changes, scientists screen each mouse’s DNA in a process called genotyping. The page reviews key mouse genetics terms,...

Chicken embryo gene delivery by electroporation lets researchers add genetic material to cells inside a developing egg. The method is used in biomedical research to change gene expression in early developing chicks kept within their eggshells. It gives scientists a way to study how genes act during development.

In the procedure, DNA or knockdown constructs are first injected into a target tissue. These materials cannot easily cross the plasma membrane on their own, so they would not enter the...

Zebrafish embryo collection and preparation are important steps in developmental biology research. Zebrafish, or Danio rerio, are a useful model organism because they are very fertile and can produce hundreds of offspring each week. Their embryos also develop quickly and are transparent, which makes early growth easy to observe.

The process begins with an overview of zebrafish mating behavior and the setup of controlled crosses. Specialized breeding tanks are used so mating can be managed...

Mouse injection routes are used to deliver experimental agents for many kinds of studies. In mice, these treatments may be used to test a therapy, trigger a disease state, or give anesthesia or palliative care. Safe and efficient delivery starts with planning the treatment before it is given.

Several agent properties must be considered first. These include viscosity, dose, and palatability, which is how acceptable a substance is to the animal. The video also reviews the syringe and needle,...

Chick embryo ex ovo culture keeps the embryo outside the eggshell for easier study and handling. The chicken embryo is a useful model for developmental biology because it develops outside the female and is easy to access for experiments. Scientists often study embryos inside the shell, or in ovo, but access can become harder at later stages of development.

Ex ovo culture solves that problem by moving the embryo outside the shell. This gives better access to tissues that may be blocked by the...

Zebrafish embryo injection is a way to change gene activity in early development. Researchers deliver genetic material or knockdown constructs into blastomeres, the embryonic cells that sit on top of the yolk in a newly fertilized egg. The method can place material directly into the blastomere or into the yolk, where natural cytoplasmic movement can carry it into the cytoplasm.

The procedure depends on the right tools and careful setup. The key equipment includes the injection apparatus and...