using gene technologies to asses genetic diversity

Question 1

describe the DNA of a species that has evolved from another species

Answer 1

the DNA will be very similar to the species it evolved from

Question 2

what can mutations cause in new species?

Answer 2

changes the base sequence, over time the DNA will accumulate more differences between species

Question 3

what is DNA hybridisation?

Answer 3

a technique used to determine the similarities between DNA sequences of different organisms

Question 4

explain how DNA hybridisation works

Answer 4

DNA separates when heated and recombines to form the original strand when left to cool. All strands within a DNA mixture will pair up with their partners eventually

Question 5

explain step by step how DNA hybridisation works

Answer 5

1. DNA from 2 species is extracted, purified and cut. DNA from one species is labelled with a radioactive marker
   2.heat breaks hydrogen bonds and separated strands.
2. mixing and cooling of strands allows hydrogen bonds to reform
3. complementary bases joined together by hydrogen bonds, non complementary bases can’t join together

Question 6

explain the results of DNA hybridisation

Answer 6

in hybrid strands where the 2 species are closely related, there is a higher number of base pairs. When the species are distantly related, there are fewer base pairs.

Question 7

when is a higher temperature needed to separate the 2 strands in DNA hybridisation?

Answer 7

when they’re closely related species so more hydrogen bonds

Question 8

when is a lower temperature needed to separate the 2 strands in DNA hybridisation?

Answer 8

when they’re distantly related species so less hydrogen bonds

Question 9

why is the DNA from one species labelled with a radioactive marker in DNA hybridisation?

Answer 9

to be able to see if the strands from the same DNA/species join up or its 50/50. You can be certain that its hybridised

Question 10

how can amino acids be used to asses genetic diversity?

Answer 10

the similarity between the amino acid sequence of the same protein, often cytochrome C, in different species will indicate how closely related they are

Question 11

comparing the base sequence of a gene provides more info than comparing the amino acid sequence for which the gene codes. Explain why

Answer 11

because the amino acid sequence could be degenerate, meaning different base triplets could code for the same amino acid so you can be certain that the DNA base sequence is identical