Molecular Homology Flashcards

Molecular Homology Concepts

• Amino Acid Sequence: Fundamental to protein structure; defines the arrangement of 20 different amino acids in polypeptides.
• Bioinformatics: Integrates computer science with biology to manage and analyze vast biological datasets.
• Clade: A segment of a cladogram that includes a common ancestor and all its descendants, reflecting evolutionary relationships.
• Cladogram: A diagram used to illustrate hypothetical evolutionary relationships among various species.
• Comparative Genomics: Focuses on contrasting DNA sequences, gene arrangements, and chromosome structures across species.
• Conjugation: A process in bacteria where two cells connect to transfer genetic material directly.

Genetic Relationships

• Conserved Sequences: Refers to unchanged amino acids in polypeptide sequences or nucleotides in DNA over evolutionary time, indicating stability.
• Distance Method: An evolutionary analysis technique that evaluates genetic distances between species to infer relationships.
• Divergent Evolution: Occurs when one ancestral species splits to form multiple descendant species, leading to diversity.
• DNA Barcode: A specific nucleotide sequence that uniquely identifies a species, subspecies, or variety.

Molecular Techniques

• DNA-DNA Hybridisation: A method to assess DNA similarity between species through the separation and recombination of DNA strands.
• DNA Sequence: The arrangement of four nucleotide types in a DNA segment, fundamental to genetic coding.
• Evolutionary Developmental Biology: Examines how species evolve and develop by comparing embryonic stages across different organisms.
• Evolutionary Distance: Measures the genetic change (substitutions) in homologous sequences since two organisms diverged.

Gene Dynamics

• Gene Duplication: The formation of an additional copy of a gene due to chromosomal mutations or polyploidy, crucial for evolutionary diversity.
• Homologous Genes: Genes that share sequences, indicating a common ancestor, with examples found in different or same species.
• Horizontal Gene Transfer: Allows for genetic material incorporation between different organisms, often seen in bacteria.

Phylogenetic Analysis

• Node: Represents a common ancestor in phylogenetic trees, marking points where species divergence occurs.
• Orthologues: Genes across different species that diverged due to speciation from a common ancestor.
• Paralogues: Genes within the same species that arise from gene duplication and exhibit mutations over time.
• Monophyletic Group: A category of species that descend from a single common ancestor.
• Paraphyletic Group: A taxonomic group that includes some but not all descendants of a common ancestor.

Evolutionary Trees and Models

• Phylogenetic Tree: Visual representation exhibiting the evolutionary relationships among species.
• Phylogram: A type of phylogenetic tree where branch lengths correlate to the number of genetic changes.
• Molecular Clock: Estimates the time since divergence by measuring accumulated genetic substitutions.

Genetic Mechanisms

• Master Control Gene: Regulates the expression of multiple genes influencing body structures and cell differentiation during development.
• Regulatory Gene: Produces factors that control the activation or deactivation of other genes.

Additional Concepts

• Pseudogene: Non-functional genes resulting from mutations during evolution.
• Synteny: The preservation of gene order in chromosome segments across different species.
• Systematics: Classifies organisms based on their evolutionary histories, significant for taxonomy and conservation.