30
COUNTRY LIFE IN BC • SEPTEMBER 2019
The symbiotic relationships in pregnancy Study of conception in cattle identifies 10,000 genes involved in bonding uterus, embryo
According to the Canadian
Cattlemen’s Association, Canada is one of the largest exporters of red meat
Research by MARGARET EVANS
and livestock, exporting around 45% of beef and cattle each year. Right behind the beef industry, Canada’s dairy industry ranks second (based on farm cash receipts) in the agriculture sector with net farm receipts for milk and dairy products totaling $6.56 billion. Central to a farm’s beef or dairy operation is a healthy herd with reproductive success. But a cow’s successful pregnancy can vary widely due to many factors. At Auburn University in Auburn, Alabama, researchers have been studying the complexities of early pregnancy in beef cattle and, for the first time, they have performed integrative analyses of the pairing of the embryo in the uterus and the endometrium, or the lining of the uterus. This pairing is a unique relationship with many genes playing a role. “Before our work was done, several studies had analyzed the conceptus [embryo] or the endometrium
separately,” says Fernando Biase, assistant professor in the Department of Animal Sciences and leader of the project. “However, a pregnancy is not made possible by the conceptus alone or the endometrium alone. We called it an integrative analysis because we were able to analyze pregnancies as a pair composed of the conceptus and the endometrium
[and] integrate the data from one component of the pregnancy with data from the other.” He says that when the embryo
arrives in the uterus, the establishment of a pregnancy is highly dependent on molecular signals; they identified over 10,000 genes involved in the bonding of the embryo and the uterus. Significantly, several hundred of those genes (223 in the embryo and 212 in the endometrium) produce molecular messages leading to distinguishable profiles unique to each pregnancy. “That means that, collectively, these messages form a unique molecular blueprint for each pregnancy,” says Biase. “Each pregnancy has a specific quantitative combination of those molecules. That makes each pregnancy unique in the sense that the mother and conceptus are fine- tuning their molecular profiles to carry the pregnancy forward. “That is not what makes each calf
unique. The genetic combination coming from the sire and the dam
makes each individual unique.” But early in the pregnancy, the
embryo and the mother create a unique bonding moment and, while there are no strict guidelines for a successful pregnancy, there is a window of normality. Much of a pregnancy’s success is the number of genes involved and the researchers were surprised when they discovered over 10,000 genes in play during that bonding event. “At first, I was very surprised,” says
Biase. “It took a lot of crosschecking to make sure that I was not making a mistake. But, when we think deeper about pregnancy, it is such a complex yet beautifully orchestrated process taking place between the conceptus and endometrium that it made sense to us. As these two entities are facing each other, with very tight connections between their outer layers and having a coordinated development as the pregnancy progresses, it is inevitable that a great proportion of the genes, if not all, are working in a coordinated way.” He explained that they, along with other scientists, have shown that the endometrium acts as a sensor to the embryo so they were aware that the endometrium could respond differently depending whether it was produced naturally or by artificial reproductive technologies. “However, we were surprised to learn that the endometrium has the
plasticity and the molecular sensitivity to adapt to the embryo it harbours. This is a critical period because the embryo is transitioning from a fairly independent period (pre-implantation period) to a period where the uterus becomes absolutely needed for further development to take place.” Understanding the successful bonding of an embryo and the uterus sets the groundline for research into failed pregnancies. Biase says that, in general, by day 25 to 30 of a pregnancy, over 35% of cows will have experienced some form of early embryo loss. The next research stage is to study what happens when things become abnormal. He says that most of the implications for pregnancy losses are happening at the attachment phase in both normal pregnancies and those initiated by other reproductive technologies. “We have an ongoing project that will evaluate the weak links on the connection between conceptus and endometrium that lead to pregnancy loss,” he says. “We will study pregnancies produced by embryo transfer as a model of pregnancy loss to understand why those conceptuses die at the early stages of development.”
Biase was joined by researchers
from the French National Institute for Agricultural Research and the University of California, Davis. The study was featured in PLOS Biology.
PLANNING TO TAP INTO THERE ARE TWO WAYS W
Seeking to increase sales in BC?
The Buy BC Partnership Program provides cost-shared funding for BC’s agri-food and seafood sectors to enhance local marketing efforts to increase sales within the province.
Next Application Deadline: November 29, 4:30pm PROGRAM FUNDING PROVIDED BY: Looking to
The BC Agrifood a project support for interprovincial (Ca
Next Applicatio PROGRAM FUNDING
Contact us today about funding opportunities:
T 250.940.6150 E
funding@iafbc.ca W
iafbc.ca
facebook.com/InvestAgBC
instagram.com/IAFBC
twitter.com/iafbc
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
