Transcription Regulators and Development

maternal mRNA

Messenger RNA molecules produced and stored in the egg by the mother before fertilization. They guide cell division and axis formation—until the embryo’s own genome becomes active and starts transcribing its own RNA

gap genes

establish the segmented body plan of the embryo along the anterior-posterior axis

pair-rule genes

They’re expressed as a result of differing concentrations of maternal proteins/gap gene proteins. They further divide the embryo into banded segments

Eve (even-skipped) gene

A pair-rule gene in drosophila that is expressed in 7 stripes along the embryo and helps establish the pattern of alternating body segments. If it’s mutated, the embryo is missing every other segment — the “even-numbered” ones are skipped

hox genes

A group of regulatory genes that control the body plan of an embryo along the head-to-tail (anterior–posterior) axis. They tell different parts of the developing body what structures to form — for example, “this segment becomes head,” “this segment gets legs,” etc.

homeobox

A short stretch of DNA inside each Hox gene that codes for a homeodomain, a protein part that can bind to DNA and turn other genes on or off

colinearity

The position of each Hox gene in the chromosome corresponds to the position in the embryo where that gene is active (front-most Hox gene controls head/neck areas, next one controls thorax, and so on toward the tail)

Evolutionary conservation (Hox genes)

Demonstrates how Hox genes are extremely similar in many ifferent animals (flies, mice, humans) because they’re so important that evolution tends to keep them

In situ hybridization

It uses labeled complementary nucleic acid
strands (probes) to localize specific RNA sequences in tissue

CRISPR-Cas9

Gene editing technology that cuts a cell's genome at a desired location, allowing for the removal of existing genes, or addition of new genes in vivo