Lecture 2: Concepts in Developmental Biology Flashcards
What directs initial developmental stages?
Maternal genes and egg cytoplasm
What directs development after cleavage?
Zygotic genes
What factors influence development over time? (2)
Gene products & environment
What concept states that all cells have the same genetic material?
Genomic equivalence
True or False: Every cell in the body has an identical genome.
False
What is the term for cells having different genetic compositions within an individual?
Genomic mosaicism
Where is genomic mosaicism mostly found?
Brain cells (neurons)
What distinguishes genomic mosaicism from epigenetic changes?
DNA sequence alterations
What is an example of a genetic alteration in neurons? (4)
- Aneuploidy
- CNVs
- SNVs
- LINE1 elements
What field relies on sequencing nonbrain DNA?
GWAS (Genome-Wide Association Studies)
What is the ability of a cell to differentiate into other cell types?
Cell potency
What is the total capacity of a cell to form a complete embryo?
Totipotency
What type of cell can differentiate into all three germ layers but not extraembryonic tissues?
Pluripotency
What type of potency allows differentiation into a restricted family of cell types?
Multipotency
Give an example of a totipotent cell.
Zygote (fertilized egg)
What type of stem cells can become blood cells but not neurons?
Hematopoietic stem cells
What is the ultimate test of nuclear potency?
Generating every cell type
What experiment tested nuclear potency using Rana pipiens eggs?
Blastula nucleus transplant
What was the first cloned mammal?
Dolly the sheep
What type of cell was Dolly cloned from?
Mammary gland cell
What was used as the enucleated oocyte donor for Dolly?
Scottish Blackface sheep
Where was Dolly implanted for development?
Surrogate Scottish Blackface sheep
What is the process by which a cell becomes specialized in structure and function?
Cell differentiation
What is the result of cell differentiation?
Cellular diversity
What part of the genome is expressed during differentiation?
A portion of the genome
What type of genes are shared by all cells?
Housekeeping genes
What type of genes are unique to specific cell types?
Luxury genes
What are undifferentiated cells with the ability to specialize into various cell types?
Stem cells
What type of stem cell can form a complete organism?
Totipotent stem cell
What type of stem cell can differentiate into cells of the three germ layers but not extraembryonic tissues?
Pluripotent stem cell
What are examples of pluripotent stem cells? (2)
- Embryonic stem cells (ESCs)
- induced pluripotent stem cells (iPSCs)
What type of stem cell can differentiate into a restricted group of related cells?
Multipotent stem cell
What type of stem cell gives rise to only one cell type?
Unipotent stem cell
What type of stem cell can differentiate into mesodermal-derived tissues like bone, cartilage, and fat?
Mesenchymal stem cells (MSCs)
Which germ layer gives rise to the gut, lungs, and liver?
Endoderm
Which germ layer forms muscles, blood, and bones?
Mesoderm
Which germ layer develops into skin and the nervous system?
Ectoderm
What is the relationship between cell differentiation and potency?
Differentiation decreases potency
What are genes that are constantly expressed in all cells for basic cellular functions?
Housekeeping genes
What is another name for housekeeping genes?
Constitutive genes
Where are housekeeping genes expressed?
All cells, all the time
What type of proteins do housekeeping genes produce?
Proteins essential for basic cellular functions
Give an example of a housekeeping gene. (3)
- Actin
- GAPDH
- ribosomal RNA genes
What are genes that are expressed only in specific cells or at specific times?
Luxury genes
What is another name for luxury genes?
Tissue-specific genes
Where are luxury genes expressed?
Only in specialized cells
What type of proteins do luxury genes produce?
Proteins related to specialized cell functions
Give an example of a luxury gene. (2)
- Hemoglobin (in red blood cells)
- myosin (in muscle cells)
What is the selective activation of certain genes depending on time and space?
Selective gene expression
What is another name for selective gene expression?
Differential gene expression
How do genes behave in selective gene expression?
Some genes are highly active in specific tissues, while others are repressed
What is a process where specific genes increase in number without mitosis?
Selective gene amplification
What is the purpose of selective gene amplification?
To meet the synthetic demands of a developing cell
What is an example of selective gene amplification?
rRNA gene amplification in amphibian oocytes
During which stage of meiosis does selective gene amplification occur in amphibian oocytes?
Early diplotene stage
What is produced in large amounts due to selective gene amplification in amphibian oocytes?
Ribosomal RNA (rRNA)
