5.Homeosis and atavism

Question 1

Homeosis

Answer 1

Transformation of one body segment into another due to changes in homeotic gene function.

Question 2

Atavism

Answer 2

Recapitulation/reappereance
of ancestral traits due to mutations or developmental errors

Question 3

Bicoid (BCD) protein

Answer 3

A maternal morphogen forming an anterior gradient that will regulate gene expression to determine head development in Drosophila.

protein-morphogen_—–gradient like the SHH

Question 4

Hunchback (hb) gene

Answer 4

A gap gene regulated by Bicoid, responsible for early segmentation and forming a boundary between head-thorax

Question 5

Homeobox

Answer 5

A conserved 180 bp of DNA sequence in homeotic genes encoding a DNA-binding domain/homeodomain.

Question 6

Homeodomain

Answer 6

A protein domain encoded by the homeobox, enabling transcription factors to bind specific DNA sequences.

Question 7

Knock-out mouse

Answer 7

A genetically modified mouse with a specific gene inactivated to study the function of the gene through resulting phenotypes.

Question 8

Segment identity genes

Answer 8

Homeotic genes that determine the specific identity of body segments, such as Antennapedia and Bithorax.

Question 9

Gill arches

Answer 9

Embryonic structures in vertebrates that develop into pharyngeal or middle ear components, regulated by homeotic genes.

Question 10

Electroporation

Answer 10

A method to introduce DNA into cells by applying an electric field to create temporary membrane pores.