Developmental Biology and Hox Genes

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Questions and Answers

What is the primary function of Hox genes in early development?

They determine the average age of embryos.

They regulate the conservation of body plans across species. (correct)

They influence emotional responses in animals.

They are responsible for the development of reproductive organs.

In the context of comparative embryology, what is a common trait observed in embryos of lizards, birds, and mammals?

Distinct organ systems visible.

Dissimilarities in genetic coding.

Similarity in head and trunk development. (correct)

Presence of fully developed extremities.

What is the relationship between phylotype and evolution as described?

Phylotype is a term used only for mammalian development.

Phylotype refers to the conserved body plan mentioned by Karl Ernst von Baer. (correct)

Phylotypes can change significantly during the course of an individual's life.

Phylotypes are specific to each individual species and do not represent broader patterns.

What distinguishes metamerism in embryos across different classes of animals?

Development of repeating body structures or segments. Signup and view all the answers

Which term describes the genotypic basis of body structure across species?

Zootype. Signup and view all the answers

What is the primary role of Hox genes during development?

Segmentation of the body plan Signup and view all the answers

Which of the following organisms is least likely to express Hox genes?

Bacteria Signup and view all the answers

What methodology is used to explore gene age in phylostratigraphy?

Using algorithms for comparative gene sequencing Signup and view all the answers

What does the stratigraphy index score indicate about genes?

The age and importance of gene families Signup and view all the answers

Metamerism in embryos is primarily characterized by what feature?

Distinct segmental organization Signup and view all the answers

What is a key concept of gene conservation in developmental biology?

Conserved genes have unchanged functions across species Signup and view all the answers

Which of the following methods is commonly used to isolate and sequence transcripts?

cDNA libraries Signup and view all the answers

Hox genes are notable for their presence in which of the following?

Select invertebrates and vertebrates Signup and view all the answers

What is the significance of Hox genes in the evolution of body plans?

They control the differentiation of body segments in bilaterians. Signup and view all the answers

What is metamerism, and how does it contribute to body structure?

It is the phenomenon where body segments are repeated and organized. Signup and view all the answers

How do Urbilaterians relate to the evolution of modern bilateral organisms?

They are the last common ancestor of all bilateral animals. Signup and view all the answers

What role does phylostratigraphy play in developmental biology?

It studies the evolutionary conservation of developmental genes. Signup and view all the answers

In comparative embryology, what aspect is primarily examined across different species?

The similarities and differences in embryonic development. Signup and view all the answers

What does the term 'generic body segments' refer to in the context of metamerism?

Repetitive units that make up a segmented body structure. Signup and view all the answers

What is the primary function of the body plan as it evolved in multicellular organisms?

To provide structural support for movement. Signup and view all the answers

Which of the following organisms are directly influenced by the same genetic set that produced the first bilaterians?

Crustaceans and mammals. Signup and view all the answers

Study Notes

What Differentiates Metameres?

Hox genes are segment selectors
Hox genes are present in organisms from sponges to humans
Hox genes are conserved and play a developmental role

What Genes Control Segment Identity?

Phylostratigraphy can be used to identify and characterize the age of genes
Phylostratigraphy compares sequences from different developmental stages of organisms to identify similar genes

Stratigraphy Index Score

The index score is assigned based on the age of the gene family
Older genes have a higher index score

How Old Are the Genes at Play During Development?

Hox genes have a high index score in early developmental stages

The Phylotype

The Phylotype is a conserved basic body plan
The Phylotype is the basis for tetrapods
Genotypic is the Zootype

Metamerism and the Phylotype

Metamerism is the repeated segmentation of the body
Metamerism is necessary for locomotion

How was the Basic Body Plan Evolved?

Multicellularity led to bilateral symmetry and a gut
The Urbilaterian is thought to be the last common ancestor of bilaterians
Hox genes are necessary to build a body plan

What is a Metamere?

A metamere is a generic body segment
Segments can be copied and repeated to build a body plan

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Description

Explore the differentiation of metameres and the role of Hox genes in segment identity and development. This quiz covers topics such as phylostratigraphy and the evolution of basic body plans, particularly in tetrapods. Test your understanding of developmental biology concepts and gene functions.