Genetics

Central Dogma

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Griffith's Experiments

Demonstrated transformation in bacteria, where genetic material from dead bacteria can be taken up by living bacteria.

Baltimore Classification of Viral Genomes

Classifies viruses based on genome type, structure, and replication strategy into seven groups.

Conjugation

Bacterial genetic transfer where a plasmid integrates into the chromosome of the recipient cell.

Meiosis

Cell division process in sexually reproducing organisms resulting in four unique gametes with half the chromosome number.

Recombination

Exchange of genetic material between homologous chromosomes during meiosis, increasing genetic variation.

Telomeres

Protective caps at the end of chromosomes that shorten with each cell division, linked to aging.

Transformation

Unidirectional transfer of extracellular DNA into recipient bacterial cells.

Operons

Clusters of genes transcribed together in prokaryotes, allowing coordinated gene regulation.

Lysogenic Cycle

Viral replication cycle where the phage DNA integrates into the host chromosome as a prophage.

Trisomy

Having an extra chromosome.

Monosomy

Missing a chromosome.

Trisomy 21, 13, 18

Only trisomies compatible with life.

Triploidy

Having three sets of chromosomes.

Binary Fission

Asexual reproduction in prokaryotes.

Mitosis

Asexual reproduction in eukaryotes.

Nucleus

Oversees cell functions and gene transcription.

Nuclear Envelope

Phospholipid bilayer with nuclear pores.

Nucleolus

Site of protein synthesis.

Chromatin

DNA state in the nucleus.

Heterochromatin

Densely packed, inactive chromatin.

Euchromatin

Loosely packed, active chromatin.

Chromosome Staining

Process to visualize chromosomes.

Metacentric

Centromere in the middle of the chromosome.

Submetacentric

Centromere between middle and end.

Acrocentric

Centromere close to the end.

Telocentric

Centromere at the end.

DNA Cloning

Amplification and propagation of DNA sequences.

Vectors

Carry DNA into a new organism for cloning.

Plasmids

Circular DNA used for cloning.

Transformation

Process to introduce foreign DNA into host cells.

Phage Lambda

A temperate phage used in cloning.

Cosmid Vector

Clones large DNA inserts.

Artificial Chromosomes

Used for cloning large DNA fragments.

Mendel's Laws

Principles of inheritance including dominance and segregation.

Punnett Square

Tool to predict genetic outcomes of crosses.

Monogenic Disorders

Disorders caused by a mutation in a single gene.

Incomplete Dominance

Heterozygous phenotype is intermediate.

Sex-Linked Genes

Genes located on sex chromosomes.

Transcription

Synthesis of mRNA from DNA.

RNA Polymerase

Enzyme for RNA synthesis in prokaryotes.

Sigma Factor

The factor that gives the enzyme specificity, now known as the holoenzyme, allowing the polymerase to identify the correct start point.

Consensus Sequences

Specific sequences in prokaryotic promoters, TTGACA (~35 bases) and TATAAT (~10 bases) before the transcription starting point, which must be similar in all promoters.

Sigma Factor Heterogeneity

Not all sigma factors are the same; they recognize different consensus sequences, e.g., sigma factor 70 recognizes -35 and -10, while sigma factor 54 recognizes -24 and -12.

Transcription Bubble

The region where RNA polymerase unwinds the DNA at the -10 box, rich in adenine and thymine, to synthesize RNA.

Polycistronic mRNA

Prokaryotic mRNA that encodes information in three-letter codons, starting with AUG (Start codon) and ending with a stop codon (UAA), allowing the ribosomes to string amino acids together.

Termination

The dissociation of the RNA polymerase holoenzyme complex from mRNA, signaled by terminator sequences forming a hairpin loop structure.

Translation

The synthesis of polypeptide chains from single amino acids directed by mRNA, ribosomes, tRNA, and amino acids, involving initiation, elongation, and termination steps.

Genetic Drift

The fluctuation of allele frequencies in a gene pool due to chance events, more pronounced in small populations, affecting genetic diversity.

Founder Effect

Occurs when a small population establishes a new colony, leading to different gene ratios compared to the original population, common in isolated groups like the Amish.

Directional Selection

A type of natural selection where a particular trait confers a survival advantage, leading to an increase in its frequency in a population over time.

Phenotypic Plasticity

The ability of a single genotype to produce multiple phenotypes in response to environmental variation.

Control of Gene Expression

Mechanisms regulating how genes are turned on or off in response to environmental cues.

Human Genome Project

Research initiative aiming to map and understand the genetic material in humans.

Encode Project

Project focused on exploring the non-coding regions of the human genome and their regulatory roles.

Epigenetic Regulation

Heritable changes in gene expression without altering the DNA sequence.

Nuclear Organization

Highly organized structure of genetic material within the nucleus.

Histone Code Hypothesis

Concept that specific combinations of histone modifications regulate gene expression.

DNA Methylation

Addition of methyl groups to DNA, often at CpG sites, influencing gene expression.

Core Promoters

Regulatory elements upstream of gene coding sequences, including promoter sequences.

Epigenetic Crosstalk

Interaction of various epigenetic mechanisms to regulate gene expression.

Non-Coding RNA

RNA molecules that play a role in epigenetic regulation and gene expression.

Genomic Imprinting

Epigenetic process silencing specific genes from each parent.

Transgenerational Epigenetic Inheritance

Non-genetic inheritance of epigenetic tags across generations.

Endocrine Disruptors & Male Fertility

Impact of environmental factors on epigenetic control of male fertility.