Module 10 Flashcards
Recapitulation theory
Embryos of higher organisms progress thru stages that lower organisms were arrested at and remained such into maturity
Meckel and Serres
Recapitulation theory (dismissed in 1800s)
von Baer
no linear sequence as in the great chain of being, based on a single body plan
Evo devo
- evolution of the genetic machinery of development
- foundational achievement is the discovery of extensive similarities in gene regulation among distantly related species with funamentally different body plans
- concentrates on the evolution of genetic toolkits
Regulatory genes
transcription factors or switches (turn other genes on or off
regulatory genes
conserved coding regions, regulatory regions and trans-acting factors, homeotic genes (hox genes)
Change in coding sequence of major regulatory genes
can have strong pleiotropic effects
change in sequence of regulatory region
produce weaker pleiotropic effects
hox genes
control body plan of embryo along head-tail axis very conserved - homolgous gene across large phylogenetic code for boyd plan not reinvented over evolutionary time!!!
C, INCREASE
) changes in transcriptional regulation can have small or large phenotypic consequences;
gene duplication events correlate with increasing cellular diversity and organismal complexity;
genes involved early development are highly conserved across highly diverged animals
lac operon
is an operon, or group of genes with a single promoter (transcribed as a single mRNA).
biogenetic law
noun: biogenetic law; plural noun: biogenetic laws
the theory that evolutionary stages are repeated in the growth of a young animal.
gene regulatory network
is a collection of molecular regulators that interact with each other and with other substances in the cell to govern the gene expression levels of mRNA and proteins.
differentiation gene batteries
A set of genes that encode proteins required for cell type-specific function, under common regulatory control by a small set of transcriptional drivers.
homeotic genes
genes which regulate the development of anatomical structures in various organisms such as echinoderms, insects, mammals, and plants.
regulatory enhancers
are DNA-regulatory elements that activate transcription of a gene or genes to higher levels than would be the case in their absence. These elements function at a distance by forming chromatin loops to bring the enhancer and target gene into proximity
homeotic mutant
Homeosis may be caused by mutations in Hox genes, found in animals, or others such as the MADS-box family in plants. Homeosis is a characteristic that has helped insects become as successful and diverse as they are. Homeotic mutations work by changing segment identity during development.
colinearity
In many animals, the organization of the Hox genes in the chromosome is the same as the order of their expression along the anterior-posterior axis of the developing animal, and are thus said to display colinearity.
PAX genes
are developmental control genes that encode transcription factors containing a DNA-binding paired domain. Mutations in three of the nine mouse genes (Pax1, Pax3 and Pax6) and two of the nine human genes (PAX3 and PAX6) are known to cause developmental defects.
MADS
Is a conserved sequence motif. The genes which contain this motif are called the MADS-box gene family.
changes in transcriptional regulation can have small or large phenotypic consequences;
BI
