development and evolution

• What are the spatial axes in developmental biology?

  • Anterior (head region)
  • Posterior (tail region)
  • Proximal (towards the center)
  • Distal (away from the center)

  
• What spatial axis corresponds to the tail region of an organism?

  Posterior

  
• What spatial axis describes the movement away from the center of an organism?

  Distal

  
• Why are spatial axes important in developmental biology?

  • Define positional information necessary for correct pattern formation
  • Coordinate gene expression to ensure proper development
  • Facilitate the differentiation of cells in specific locations

  
• How do spatial axes contribute to the correct pattern formation in an organism?

  By defining positional information necessary for correct pattern formation.

  
• How might disruptions to spatial axes affect the development of an organism?

  They could lead to genes being expressed in incorrect locations, causing developmental errors.

  
• What are Hoxa genes?

  • They are a group of homeobox genes that play a major role in body plan development.
  • They are involved in determining segment identity along the anterior-posterior axis.

  
• What are Hoxd genes?

  • They are another group of homeobox genes that are essential for limb development.
  • They are involved in determining the identity of limb segments along the proximal-distal axis.

  
• How do Hox genes influence limb development?

  They control segment identity along the anterior-posterior and proximal-distal axes, determining the specific characteristics of different body regions and limb segments.

  
• What is the role of Hoxa9 genes in development?

  Hoxa9 genes determine segment identity along the anterior-posterior axis during body plan development.

  
• What is the role of Hoxa9-11 genes in development?

  Hoxa9-11 genes define a specific region along the anterior-posterior axis during body plan development.

  
• What is the role of Hoxa9-13 genes in development?

  Hoxa9-13 genes are a cluster of homeobox genes that specify segment identity along the anterior-posterior axis, contributing to the overall body plan development.

  
• What is the role of Hoxd9 genes in development?

  Hoxd9 genes determine segment identity along the proximal-distal axis during limb development.

  
• What is the role of Hoxd9-13 genes in development?

  Hoxd9-13 genes specify segment identity along the proximal-distal axis, contributing to limb formation and segment differentiation.

  
• What is the role of Hoxd9-11 genes in development?

  Hoxd9-11 genes determine a specific region along the proximal-distal axis during limb development.

  
• How do Hoxa genes and Hoxd genes differ in their functions?

  • Hoxa genes:
  • Involved in body plan development
  • Determine segment identity along the anterior-posterior axis
  • Hoxd genes:
  • Involved in limb development
  • Determine segment identity along the proximal-distal axis

  
• What are the key axes influenced by Hox genes in development?

  Anterior-posterior axis and proximal-distal axis.

  
• What are the two main categories of Hox genes mentioned in the study material?

  • Hoxa genes
  • Hoxd genes

  
• What are the two main processes regulated in the limb bud by the ZPA and AER?

  • Growth
  • Pattern

  
• How does $Shh$ from the ZPA influence limb patterning?


  • $Shh$ diffuses to establish anterior-posterior polarity, influencing digit identity and number.

  
• What is the function of $Fgf$ in limb development?


  $Fgf$ promotes limb growth.

  
• What region is responsible for limb growth in the limb bud?

  The AER (Apical Ectodermal Ridge).

  
• What do ZPA and AER stand for in limb development?

  • ZPA: Zone of Polarizing Activity
  • AER: Apical Ectodermal Ridge

  
• How does $Shh$ from the ZPA influence limb patterning?


  • $Shh$ diffuses to establish anterior-posterior polarity, influencing digit identity and number.

  
• What are the two main processes regulated in the limb bud by the ZPA and AER?

  • Growth
  • Pattern

  
• What do ZPA and AER stand for in limb development?

  • ZPA: Zone of Polarizing Activity
  • AER: Apical Ectodermal Ridge

  
• What are the four main bones of the human pelvic girdle?

  The ilium, ischium, pubis, and femur.

  
• What are the main functions of the human pelvic girdle?

  • Supports the weight of the body
  • Protects internal organs
  • Facilitates movement of the lower limbs
  • Serves as an attachment point for muscles

  
• Which bone of the pelvic girdle connects to the femur?

  The ilium.

  
• Which bone of the pelvic girdle is anterior and connects to the sacrum?

  The pubis.

  
• What is the largest bone of the leg that articulates with the pelvic girdle?

  The femur.

  
• What is the name of the lower part of the pelvic girdle that provides support for sitting?

  The ischium.

  
• What are the three embryonic stages shown in the images?

  • Embryonic stage E10.5F
  • Embryonic stage E12K
  • Embryonic stage E14

  
• What are the two main components of a limb?

  Skeleton and muscle.
• Where does the musculature of the limb originate from?

  • From the somite
• From which mesoderm region does the limb skeleton develop?

  Lateral Plate Mesoderm (LPM).
• What are the key features of the Lateral Plate Mesoderm?

  • Most lateral region of the mesoderm layer
  • Majority of the limb comes from the LPM
• Where does the lateral plate mesoderm run along the body?

  The majority of the trunk.
• Where is the lateral plate mesoderm located in relation to the somites?

  Lateral to the somites.
• In how many discrete places do limbs typically form?

  Two: forelimb and hindlimb.