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Flashcards in Lecture 18 Deck (34)
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1

What is the name given to the representation of the differences between species and their evolution from common ancestors

Phylogenetic tree

2

It has been shown that most of the genes across kingdom Animalia have been relatively conserved. How has this been achieved

BLAST analysis of protein structures to determine regions of significant homology

3

It was determined that what makes members of the animal phyla different is not differences in the genetic sequence as such but what difference was seen

Changes in expression of a common set of genes

4

For great apes and man the change in the nucleotide sequence is about 1% every 10million years, T or F

T

5

If the human and great ape nucleotide sequence changes by roughly 1% every 10 million years and the common ancestor of humans and chimpanzees evolved 5 million years ago, how different are their genomes. Represent this as a fraction and as a number of nucleotides

0.5% difference – 1 in 200 nucleotides

6

Firstly, molecular data is used to distinguish specices which is then backed up by morphological data, T or F

F – vice versa

7

When assembling the phylogenetic tree a specific gene is used to determine relation, this gene is FOXP2. Why is FOXP2 used as a way of differentiating between species

FOXP2 is a highly conserved protein which only shows differences at a few positions in the amino acid sequence

8

Which positions in the amino acid sequence does the FOXP2 vary

80, 303 and 325

9

Mice and chimps both have a threonine residue at position 303, what therefore can be inferred about the common ancestor of these species

Their common ancestor must have also had a 303T

10

Humans and chimps both have 80D in the FOXP2 gene meaning that the common ancestor between these species also possess an 80D. Which amino acid is denoted by D

Aspartate

11

When sorting animals into phyla, programmes similar to BLAST consider all possible relations between animals. How are they then sorted

The tree is assembled based on the simplest model with the fewest changes

12

What is meant by the term parsimony

The idea that you always assume the simplest model

13

Convergent evolution goes against the parsimony model. How does convergent evolution account for differences in the amino acid sequence

Changes in the amino acid sequence of two animals occur independently of each other

14

When assembling the phylogenetic tree, molecular phylogeny is compared with morphological phylogeny and fossil records to give us a deeper understanding of evolution, T or F

T

15

Although there are only 4 families of vertebrate FGF receptors, how many distinct receptors are there

22

16

The Ciona or sea squirt is a distant vertebrate ancestor that only contains 4 FGF receptors. What does this tell us about the common ancestor of Ciona and modern vertebrates

The common ancestor also had only 4 FGF receptors

17

What can explain the other 16 FGF receptors present in vertebrates that aren’t in sea squirts

These will likely have arisen due to genome duplication both locally and by ploidy events

18

What is the name given to a duplicated gene present in the genome

Paralogue

19

Chromosome duplications or duplication mutations are seen frequently when comparing genomes, T or F

T

20

When a gene is first duplicated, what is its role

It is redundant

21

Over time duplicated genes evolve allowing a refinement of function or for a new function to development, T or F

T

22

What ways can the extra copy of a gene change

Can change the pattern of gene expression or the structure/function of the protein

23

Big changes to protein structure are caused by what type of mutations

Domain swapping

24

Smaller changes in the protein structure of a duplicated gene are caused by nonsense mutations, T or F

F – missense mutations

25

What is considered to be the common driving force for morphological evolution of animals

Changes in expression of genes

26

What changes in the transcription machinery present within the DNA explain why expression pattern changes have a major role in morphological evolution

Enhancers can change easily

27

What process can account for bringing a new enhancer regions close to the coding sequence of a gene

Non-homologous recombination

28

Enhancers must occur upstream of a target gene, T or F

F – enhancers can occur anywhere in the gene sequence and their exact position is usually unimportant

29

Changes in protein structure have to be precise so as not to introduce a variety of negative effects. Give some examples of these effects

Introduction of a stop codon, change in the reading frame, interference with protein folding or a disruption in RNA splicing

30

Describe the differences seen in the development of appendages in the fruit fly and Crustacea

Crustaceans development limbs throughout their abdominal and thoracic segments whereas in Drosophila, no legs develop in the abdominal regions