BIOL 215 Micro Evolution

Question 1

What are variations for evolution ?

Answer 1

It is the fuel for evolution.

Question 2

What are the [4] types of variations ?

Answer 2

Variation in chromosomes number
Mutations
Epigenetic variation
Phenotypic variation

Question 3

What are the two major changes that can happen in chromosomes ?

Answer 3

Number of chromosomes in the entire set 
Number of single chromosomes
Mix of chromosomes of two different species ex: wheat that comes from Triticum monococcum (wild einkorn)
and a species of Aegilops (goat grass)
Change in the structure of chromosomes

Question 4

Chromosomes variation

What is polyploidy ?

Answer 4

When a specie double its number of chromosome, creating a whole new specie. ex: evil weed in laboratory

Question 5

Chromosomes variation

What are the types of structural changes that can occur in chromosomes ?

Answer 5

Deletion
Duplication
Paracentric inversion (sequence is reversed between telomeres and centromere)
Pericentric inversion (sequence is reversed on both side of the centromere)
Reciprocal translocation (two ends of different chromosomes exchange sequences)

Question 6

The Chineese and the Indian muntjac look almost the same. Why are they in fact different species ?

Answer 6

The chineese muntjac have 23 pairs of chromosomes and the Indian muntjac have 2 pairs + 3 sexual chromosomes.

Question 7

What are the two different consequences of mutation in a gene ?

Answer 7

It will change the protein structure, so the product, or the rate of expression of a gene or a product.

Question 8

What is gene regulation ?

Answer 8

All the signals combined together that lead to transcription, translation and activation of a specific protein. ex: presence or absence of a repressor or an activator

Question 9

What are the [3] mechanisms of gene regulation in eukaryotic cell ?

Answer 9

Cis-, trans- and RNAi-regulation : presence of elements close or far from the gene that regulates its transcription
Transposons : copies of the same sequence (ex:Alu sequence)
Posttranscriptional modification (RNA editing)

Question 10

What are the main characteristics of Hox genes and what can happen during an homeotic mutation?

Answer 10

It is really conserved sequences in animals that impart during development identity to regions along the body
axis. If a mutation occur, some parts of body could grow at places they are not supposed to (ex: legs instead of wings). Single regulatory change in a gene that controls other genes can change how a gene network works, with dramatic consequences for the phenotype.

Question 11

What are epigenetic variations ?

Answer 11

A way to meditate gene expression depending on environment. Thats why you have different size of ants because in presence of food or not, you will see hyper methylation or hypomethylation of the gene that regulates size.

Question 12

What are phenotypic variations ?

Answer 12

Variations in phenotype induced by the environment (ex: seasonal wings look in butterflies)

Question 13

Is genotypic and phenotypic variation random or is it predictable?

Answer 13

Given that some ants share the same mutations in two completly different populations, some mutations may be the result of epigenetic variation, but some types still remain random.

Question 14

What types of mutations are most likely to fuel evolution?

Answer 14

A mix of all mutations can fuel evolution. That is not variation that choses who lives and reproduces with the mutation, it is selection that will test those mutations.

Question 15

What is included in the phenotypic space ?

Answer 15

genetic background x environment x development time

Question 16

What is the main goal of evo-devo

Answer 16

Uncover the rules underlying how genes interact with their environment during development and how this affects the way evolution works.