| Date | November 2017 | Marks available | 1 | Reference code | 17N.3.HL.TZ0.09 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | 09 | Adapted from | N/A |
Question
Transgenic rainbow trout (Oncorhynchus mykiss) were produced from both wild strain and domestic strain trout, using a gene coding for growth hormone from coho salmon (Oncorhynchus kisutch). The graph shows the mean mass of the nontransgenic and transgenic trout at 8 months post-fertilization.
[Source: Reprinted by permission from Macmillan Publishers Ltd: Nature, 409, Growth of domesticated transgenic fish, R H Devlin et al., pp. 781–782, copyright 2001]
Analyse the data for the growth of nontransgenic trout and transgenic trout.
Suggest a reason for the growth differences between the nontransgenic trout and transgenic trout.
Describe the use of marker genes in the development of transgenic organisms such as trout.
Outline the possible environmental impact associated with the accidental release of transgenic trout.
Markscheme
a. both transgenic «strains» show more growth/mean mass than nontransgenic
Allow vice versa
b. wild nontransgenic «strain» showed less growth than wild transgenic
Allow vice versa
OR
greatest difference between wild nontransgenic and transgenic «strains»
OR
wild «strain» showed less growth/mean mass in nontransgenic but reverse in transgenic
c. mean mass/growth in domestic nontransgenic «strain» lower than «domestic»
transgenic
d. error bars overlap for domestic nontransgenic and transgenic «strains»
[Max 2 Marks]
gene for growth hormone has been assimilated/is expressed in the transgenic trout
OR
more growth hormone produced/expressed in transgenic trout
a. indicates successful uptake of recombinant DNA
b. identifies transgenic organisms
c. example of a marker gene
eg: antibiotic resistance gene in bacteria
[Max 2 Marks]
a. transgenes may be transferred to other species/organisms
b. may alter ecosystem/food chain
c. may outgrow other species
OR
decrease biodiversity
OR
outcompete nontransgenic individuals/trout
[Max 2 Marks]
