Introduction to Developmental Biology Lecture Series Flashcards

These vocabulary flashcards cover the fundamental principles, historical experiments, genetic mechanisms, and evolutionary concepts discussed in the Developmental Biology lecture series at IIT Madras.

Developmental Biology

The study of how an egg becomes an adult body and how the adult body produces another body, encompassing the continuation of learning what constitutes life.

Cellular Differentiation

The process by which identical embryonic cells become different kinds of specialized cells, such as neurons, muscle cells, and epidermal cells.

Morphogenesis

The process of shape formation where cells organize and take specific arrangements to form functional organs like muscle fibers or the spinal cord.

Cleavage

Rapid cell divisions following fertilization where the large oocyte cytoplasm is partitioned into smaller compartments called blastomeres without an increase in total volume.

Gastrulation

The stage where blastomeres migrate and rearrange into three major germ layers: the ectoderm, mesoderm, and endoderm.

Ectoderm

The outermost germ layer that gives rise to the skin surface, brain, neurons, and pigment-producing melanocytes.

Mesoderm

The middle germ layer that forms internal structures including the heart, blood, kidneys, bones, and muscles.

Endoderm

The innermost germ layer responsible for forming the inner linings of the digestive tube and respiratory systems like the lungs.

Organogenesis

The process where cells from the germ layers interact and undergo further rearrangements and migrations to form specific functional organs.

Metamorphosis

A remarkable developmental change where an early larval form, different from the adult, transforms into a sexually mature adult form.

Genomic Equivalence

The concept that nearly all somatic cells in an adult body contain the same set of chromosomes and genetic material as the original zygote.

Differential Gene Expression

The mechanism by which different cell types express only specific portions of the genome while temporarily inactivating others to achieve specialization.

Enhancer

A regulatory DNA sequence that controls the efficiency, rate, and tissue-specific spatial or temporal expression of a gene.

Transcription Factors

Proteins that bind to specific DNA sequences to recruit or stabilize RNA polymerase, thereby regulating the initiation of gene transcription.

CPG Islands

Chromosomal regions rich in Cytosine-Guanine repeats that are common targets for DNA methylation to repress gene transcription.

Genome Imprinting

A phenomenon involving sex-specific DNA methylation where a gene is expressed only from either the maternal or paternal allele.

Alternative Splicing

A nuclear process where different combinations of exons from a single pre-mRNA are joined to produce a family of distinct protein isoforms.

Induction

An interaction where one group of cells (the inducer) produces signals that determine the developmental fate of a neighboring group of cells (the responder).

Competence

The ability of a specific cell or tissue to respond to an inductive signal, often requiring the prior expression of specific receptors or transcription factors.

Morphogen

A signaling molecule that forms a concentration gradient, inducing different cell fates at different concentration thresholds.

Hox Genes

A conserved family of homeotic selector genes that specify the identity of body segments along the anterior-posterior axis.

Collinearity

The correspondence between the physical order of Hox genes on a chromosome and the spatial sequence of the body structures they specify.

Paracrine Signaling

A form of cell-to-cell communication where proteins secreted into the extracellular environment travel over short distances to influence neighboring cells.

Juxtacrine Signaling

Communication between cells that requires physical contact between membrane-bound ligands and membrane-bound receptors, such as the Notch-Delta pathway.

Apoptosis

A genetically programmed process of cell death used during development to sculpt structures, such as removing the webbing between human digits.

Sporophyte

The diploid, multicellular phase in the plant lifecycle that produces haploid spores through meiosis.

Gametophyte

The haploid, multicellular phase in the plant lifecycle that produces gametes (egg and sperm) through mitosis.

Heterochrony

An evolutionary change in the timing or duration of developmental events, such as the speed of vertebrae segmentation in snakes.

Heterotopy

An evolutionary variation where a gene is expressed in a new spatial location, leading to novel structures like the turtle shell or bat wing.

Heterometry

An evolutionary change in the amount of a gene product expressed, such as the varying levels of BMP4 determining beak size in Darwin's finches.

Allometry

A variation of heterometry where different parts of an organism grow at different rates, resulting in changes in body proportions over time.

Heterotypy

An evolutionary change in the coding sequence of a gene that alters the functional properties of the resulting protein, such as the loss of legs in insects.