Page 73 - CB1.3 Genetic Varation sciPAD

PHOTOCOPYING PROHIBITED
© Silverback Academic Media 73
CB 1.3 GENETIC VARIATION
USING KNOWLEDGE OF GENETICS
Genetic Diversity and the Takahē
Takahē (Porphyrio hochstetteri) are one of the world’s most endangered
birds. There are only around 440 still surviving. Due to their small
population size, very little was known about their mating systems -
are they monogamists (breeding with only one partner), or are they
like their distant relatives the pūkeko, and more promiscuous with
females having more than one male partner?
Because the remaining takahē populations are so closely managed,
understanding their breeding behaviour is important if scientists are to
increase both the population size and the genetic diversity of the takahē
population. Genetic diversity within the remaining population is extremely
important as it serves as a way for the takahē to adapt to changing environments.
With more genetic variation, it is more likely that some individuals in the population will possess
alleles that are better suited to the changing environment.
In the early 2000’s, New Zealand scientist Marieke Lettink and her colleagues used DNA technology
to study the breeding system of takahē. A sample of her team’s results is shown below. It shows
the DNA profile of a takahē family containing one female, five chicks (C1-C5), and three potential
fathers (M1-M3)
Chicks Males
Female C1 C2 C3 C4 C5 M1 M3
M2
1. Identify which of the males fathered the takahē chicks. 
2. State whether the evidence shows takahē have monogamous or promiscuous breeding
behaviour. 
3. Understanding takahē breeding behaviour is important to ensure that scientists can
maintain genetic diversity within the remaining takahē population. Explain why maintaining
genetic diversity is important for the survival of the takahē. 





Unchecked Sample Pages
For Review Purposes Only - Photocopying Prohibited
www.scipad.co.nz