Developmental Biology

Development Biology describes development as a sequence of processes and events, in which ‘simple’ structures such as fertilized eggs are progressively transformed into complex organisms.

Objectives of the Study of  Development Biology

• Identify a few major researchers in the development of the field of Developmental Biology and outline how our understanding of embryonic development has changed over timeTime Where any expression of it occurs in any Rules, or any judgment, order or direction, and whenever the doing or not doing of anything at a certain time of the day or night or during a certain part of the day or night has an effect in law, that time is, unless it is otherwise specifically stated, held to be standard time as used in a particular country or state. (In Physics, time and Space never exist actually-“quantum entanglement”).
• Know the characteristics of the major experimental model organisms
• Identify and define the major stages in the development of model organisms
• Demonstrate an understanding of selected molecular techniques used in the field of Developmental Biology
• Demonstrate an understanding of the process of gamete production and fertilization
• Understand the steps involved in cleavage and gastrulation and also identify the types of cellCell The smallest unit that can live on its own and that makes up all living organisms and the tissues of the body. A cell has three main parts: the cell membrane, the nucleus, and the cytoplasm. The cell membrane surrounds the cell and controls the substances that go into and out of the cell. The nucleus is a structure inside the cell that contains the nucleolus and most of the cell’s DNA. It is also where most RNA is made. The cytoplasm is the fluid inside the cell. It contains other tiny cell parts that have specific functions, including the Golgi complex, the mitochondria, and the endoplasmic reticulum. The cytoplasm is where most chemical reactions take place and where most proteins are made. The human body has more than 30 trillion cells. movements involved in gastrulation
• Distinguish between germ layers and list what tissues/organs develop from each germ layer
• Describe mechanisms by which embryonic cells communicate and their role in regulating embryonic development
• Describe the mechanism of gene expression regulation and explain their importance in controlling developmental processes
• Outline the processes involved in generating a nervous system
• Outline the process involved in limb development
• Identify and differentiate between mechanisms used to develop a complex, multicellular organism.
• Outline the differences and similarities between plant and animal development and demonstrate an understanding for the basis for these differences
• Demonstrate an understanding of the process of pollination and fertilization
• Describe the structure of apical meristems and their role in development
• Demonstrate an understanding of the principal mechanisms that regulate leaf, flower and root development
• Explain the significance of hormones in plant development and describe the role of each of the five major hormones in development
• Identify embryonic structures in slide preparations, photographs and diagrams

Animal Development

Introduction to animal developmental biology
What is developmental biology?
Model organisms
Overview and comparison of early development in vertebrates (Xenopus)

Origin and approaches to animal developmental biology
Origins of developmental biology (early theories)
Anatomical approaches
Experimental approaches
Genetic approaches

Germ cells, gametogenesis and fertilization
Specification of germ cells
Oogenesis and spermatogenesis
Fertilization and prevention of polyspermy
Parthenogenesis

Cleavage: mechanisms, patterns and consequences

Cleavage cycle
Patterns and type of cleavage
Formation of the blastula

Morphogenesis

Cell shape, adhesion and movements
Morphogenic processes in gastrulation and neurulation
Molecular basis of gastrulation and neurulation

Axis formation: setting up the body axis

Dorsoventral and anteroposterior axis formation
Establishing left-right asymmetry

Cell specification and determination

Progressive determination of cell fate
Cell-cell communication
Acquisition of commitment
Eye development as an example of induction in development

Germ layer origin and specification

Mesoderm induction
Mesoderm patterning along the dorso-ventral and antero-posterior axes
Ectoderm and endoderm specification (Xenopus)
CRISPR and human genome editing

Antero-posterior patterning and somites; Neural tube induction

Somite specification and formation
Role of Hox genesGenes The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein. Structure of DNA; drawing shows a chromosome, nucleosome, histone, gene, and nucleotide base pairs: guanine, cytosine, adenine, and thymine. Also shown is a cell and its nucleus. Structure of DNA. Most DNA is found inside the nucleus of a cell, where it forms the chromosomes. Chromosomes have proteins called histones that bind to DNA. DNA has two strands that twist into the shape of a spiral ladder called a helix. DNA is made up of four building blocks called nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C). The nucleotides attach to each other (A with T, and G with C) to form chemical bonds called base pairs, which connect the two DNA strands. Genes are short pieces of DNA that carry specific genetic information. Genetic risk is a major component of many diseases, modification of the human genome is perhaps the most precise way to reduce those risks. Direct and safe manipulation of the human genome is rapidly becoming a reality with the advent of precision genome engineering techniques. in A-P patterning
Neural tube induction

Neural crest cells; cell differentiation

Neural crest cells origin, migration and patterning
Differential gene expression
Models of cell differentiation
Plasticity of gene expression

Neural tube patterning/organizing the developing nervous system

Limb development

Limb bud induction and formation
Development along the proximal-distal axis
Development in the dorsal ventral-axis
Digit specification and separation

Plant Development

Embryogenesis, seed development and germination
Stages in embryo development
Seed structure
Endosperm development
Germination

Introduction to phytohormones

What are phytohormones?
How hormones work –roles in development

Establishing the body plan: apical-basal and radial patterning

Embryo fate map
Specification of cell fate along the apical-basal axis
Hormones in apical-basal patterning
Radial pattern formation

Meristems

Types of meristems
Shoot apical meristems organization and maintenance
Root apical meristem, structure, specification and maintenance
Hormonal regulation of apical meristem activity

Development of lateral organs

Auxillary meristems and shoot branching
Positioning of lateral organs on the shoot apical meristem
Initiation and development of lateral roots

Axis formation in leaves

Leaf morphology
Initiation of leaf development
Genetic control of leaf identity and complexity
Establishing leaf polarity and patterning

Patterning the epidermis (stomata, trichome and root hair)

Stomata structure and function
Guard cell fate specification and patterning
Trichome structure and function
Trichome fate specification and patterning
Root hair structure and function
Root hair fate specification and patterning

Gametophyte development and fertilization

Alternation of generations – haploid phase
Pollen grain structure and development
Ovule and embryo sac structure and development
Cell fate specification in the embryo sac

Flower development

Floral meristems
How to make a flower
Establishing floral meristem identity and determinacy
Determining floral organ identity: The ABC model