Why I choose
sex
Tamara Leahy
PhD student
Overview
Agriculture is a cutting-edge industry with more to it than just growing crops and milking cows.
At Uni, I became fascinated by the fact that we can improve productivity of animals by understanding
and improving their efficiency to reproduce.
I’m going to show you the vital role of sex in agriculture.
Background
I was fascinated by animals from a young age…
Photo: Tamara 6 months old, petting zoo
and became one of the few who actually ended up doing what they wanted to do at age 6
“When I grow up I am going to be an animal breeder”
Photo: Tamara 6 years, pony club
From Ponies
to Elephants
to Tigers
Riding Peow-Pong in Ko Lanta
It doesn’t get any better than this. Working with
animals all over the world.
Why is agriculture
important?
Agriculture in Australia is of cultural, environmental and economic importance
ANIMALS ARE A BIG PART OF IT
Yeah, but Kevin Rudd took all the
credit.
Did you hear the rural sector saved Australia
from recession.
Assisted reproductive
technologies in agriculture
What is the purpose?
Can’t they do it alone?
What are assisted reproductive technologies?
Assisted reproductive technology (ART) is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means.
Artificial insemination
Process in which sperm are placed in the female tract to facilitate fertilisation
Collection
Intrauterine insemination
How is AI done??
Semen can be deposited directly
into the vagina, cervix or uterus
Image: www.wiki.ucalgary.ca
/
Sperm Freezing
Removes temporal and spatial (time and space) restrictions to distribution of superior genetics
This gives animal breeders more choice when selecting genetically desired traits
Image: www.isisrfc.com/cryopreservation.php
ART advantages include:
The ability to freeze semen helps to ensure the survival of rare gene pools, for example endangered species.
Image: www.messiah.edu
Australian Innovators Australia is considered to be
• ahead of competitors in the use of genetic markers and artificial insemination for breeding.
• on par with competitors in the use of DNA-based and protein-based diagnostic tests and disease treatments.
Value of Biotechnology to Australian Economy:www.daff.gov.au/__data/assets/pdf_file/0003/437601/non-gm-report.pdf
The next exciting step is being able to determine the sex of the
offspring
SEX
SELECTION
Did you know? A few animals can determine the sex of their offspring naturally but maybe we can help them all and couldn’t we do wondrous things if we did?
• Sex of crocodiles is determined by egg incubation temperature.
• Nemo or Nema? The head male clown fish will turn into a female to maintain social structure if head female dies.
Image http://scienceblogs.com
What to know more:www.genetics.com.au/factsheet/index.asp
In mammals (including ourselves)
sex is determined by
chromosomes
Males have X or Y
chromosome-bearing
sperm
Females only have X
X + X = Female
Y + X = Male
How?
• Many weird and wonderful techniques have been reported to determine the sex of offspring but the only reliable method is separation based on DNA content (X larger than Y).
• The sperm are stained and processed through a machine.
• A laser in the machine is used to differentiate between sperm that contain a X or Y chromosomes.
Why?
In the agricultural sector sex-selection is most beneficial in industries in which production traits are sex-linked.
For example a dairy farmer may want more female calves to produce milk.
But there are many other reasons why sex may be pre-determined for example:
1) Social: In zoos to maintain normal social structure (usually one male many females)
2) Medical: To prevent sex-linked diseases of humans such as haemophilia.
3) Ecological: Increasing numbers of threatened species
Now this is a nice social
experience!!!!
The problem
Sperm are damaged by sex-sorting and
freezing....
reducing their ability to complete
their mission – to fertilise the egg.
Image: www.kcl.ac.uk
My PhD studies
To explore ways to
protect sperm during
processing for freezing and
sex-sorting
Target animal = sheep
Introduction
• We predicted the fluid, termed seminal plasma, in which the sperm are suspended in upon ejaculation may be the answer to protecting sperm during freezing and sorting.
• We already know that seminal plasma contains proteins that can protect the sperm from certain types of stress.
• So, we reasoned that that we could add these proteins to the sperm and protect them from damage at both the sexing and freezing stages.
Results
We found:
• stressors of sex-sorting cause ram sperm to become more susceptible to reactive oxygen species (oxidative stress)
• Preliminary results suggest this may be due to mechanical insult during processing for sex-sorting
• Addition of seminal plasma proteins or antioxidants (catalase) protects sperm from oxidative damage
Summary
We have had some success and improved fertility but nothing is ever simple and we have identified that:
• The response is variable • It depends on:
• The season of the year seminal plasma is collected .
• At what part of the process the proteins are added.
• How you add the proteins.
So that’s why I choose sex. There is still a lot of work to be done and there is certainly room in our team if
you want to be part of the excitement?
Photo: Tamara 25 years, friendly cow in Spain
We need you on our team In many cases, Australia’s competitors are also placing considerable effort in developing biotechnology
applications for agriculture. Australia is considered generally to be ahead of competitors in the use of genetic markers and artificial insemination for breeding, and is on par with competitors in the use of DNA-based and protein-based diagnostic tests and disease treatments. However, Australia’s agricultural competitors are well ahead in many other areas, including:
• some genome sequencing projects involving Australian species, e.g. Eucalyptus spp;
• proteomics for agriculture (Australia being on par regarding proteomics for human health);
• development of new vaccines (e.g. sub-unit vaccines) for livestock applications;
• biofuels;
• functional foods and nutraceuticals (based on waste products from agriculture); and
• use of biotechnology in the fibre industry.
Further, competitors that have been considered behind Australia in the past, including Brazil and China, are catching up fast. Australia needs to ensure that efforts continue to be applied to developing biotechnology applications where domestic challenges are presented (e.g. high boron soils, salinity, drought, region specific disease strains, and insecurity).
Australia also needs to ensure it captures international developments which are relevant to Australian agriculture (e.g. vaccines and diagnostic tests for diseases which are common elsewhere).
Read all about Biotechnology in Australia here:www.daff.gov.au/__data/assets/pdf_file/0003/437601/non-gm-report.pdf
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This is a Tamara Leahy presentation
for the 2009