DNA Technology

Question 1

Why is new or improved technologies important?

Answer 1

New discoveries being made

Relationships between organisms being clarified

Leading to classification systems updated

Question 2

Three examples of the advances in classifying evolutionary relationships

Answer 2

• Genome sequencing
• Comparing amino acid sequence
• Immunlogical comparisons

Question 3

Why is advance in genome sequence can find?

Answer 3

• The entire base sequence of an organism’s DNA can be determined
• DNA base sequence of one organism can be compared to the DNA base sequence of another organism to see how closely related they are

Question 4

What happens to closely related species with genome sequencing?

Answer 4

A higher percentage of similarity in their DNA base order

e.g humans and chimps share around 94% humans and mice share 80%

Question 5

How have genome sequencing helped in skunks?

Answer 5

• Clarified relationships between skunks and members of the Mustelidae family(e.g weasels and badgers)
• Skunks were classified in the Mustelidae family until their DNA sequence was revealed to be significantly different to other members of the family
• reclassified into the family Mephitidae

Question 6

What are proteins made up of?

Answer 6

Amino acids

Question 7

How can comparing amino acid sequence help?

Answer 7

• Sequence of amino acids in a protein coded for by the base sequence of DNA

Question 8

What happens with related organisms with comparing amino acid sequence?

Answer 8

• Related organisms have similar DNA sequences and so mant similar amino acid sequences in their proteins
  e. g ctochrome C is a short protein found in many species

The more similar the amino acid sequence of cytochrome C in two different species, the more closely related the species are likely to be

Question 9

What is immunological comparisons?

Answer 9

• Similar proteins will also bind the same antibodies
  e. g if antibodies to a human verison of a protein were added to isolated samples from some other species

any protein thats like the human verison will be recongised (bound) by that antibody

Question 10

What does this table show?

Answer 10

Data shows species A and B are more closely related to each other

than either C or D

Species C and D are more closely related to each other than A and B

Question 11

What does this amino acid sequence show?

Answer 11

A and B species are very similar

C is different to any other species

A and Be are more closely related

Question 12

What is genetic diversity?

Answer 12

Number of different alleles in a population

Question 13

How did early estimates are easier?

Answer 13

Made by looking at the frequency of measurable/observable characteristics in a population

e.g different eye colours in a population and number of people with each particular eye colour

Question 14

What do different alleles determine?

Answer 14

Determine different characteristics

a wide variety of each characteristics in population indicate a high number of different alleles

high genetic diversity

Question 15

What do gene technologies measure?

Answer 15

Genetic diversity

Question 16

Why comparing DNA sequence of same gene in different organisms measure genetic diversity?

Answer 16

Allow scientist to find out how many alleles of that gene are there are in that population

different alleles also produce slightly different mRNA base sequences and may produce proteins with slightly different amino acid sequences so these can be compared

Question 17

Why are new technologies important?

Answer 17

• Give a more accurate estimates of genetic diversity within a population or species
• Allows genetic diversity of different species to be compared easily

Question 18

The amino acid sequence of the insulin protein was determined for humans, horses and chickens. When this was done, it was found that horse insluin was more similar to human insulin than chicken insulin

What does these results suggest?

Answer 18

Horses are more closely related to humans than chickens

Question 19

The colour and pattern of the shells of the snail species Cepaesa nemoralis is controlled by several genes, each of which has several alleles. A scientist interested in the species thinks that there may be more genetic diversity in genes controlling shell colour and pattern in population of snails from warmer climates than in populations of snails from colder climates

a) Describe and explain how comparing DNA sequences of individuals from different populations could be used to test this theory

Answer 19

Should compare DNA base sequences of a gene controlling the shell coour or pattern inindividuals from a warm climate to a cold climate

Different alleles of the same game have slightly different DNA base sequences

Determine how many alleles in the population

Repeat this for shell colour and pattern genes

Question 20

The colour and pattern of the shells of the snail species Cepaesa nemoralis is controlled by several genes, each of which has several alleles. A scientist interested in the species thinks that there may be more genetic diversity in genes controlling shell colour and pattern in population of snails from warmer climates than in populations of snails from colder climates

b) Before gene technologies like this became available, how was genetic diversity estimated

Answer 20

By looking at the frequency of measurable/observable characteristics in the population

Question 21

What are the advantages of using gene technologies rather than traditional methods to assess genetic diversity in a population?

Answer 21

Can give more accurate estimates of genetic diversity and make comparisons of genetic diversity easier to carry out