Research Discovers Genes Linked To Twinning And Reproductive Fitness

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This article is provided by the Baylor College of Medicine, please share your comments below…..

mombabyBearing fraternal non-identical twins, or dizygotic (DZ) twinning, has been known to run in families. Studies have suggested that DZ twinning is potentially influenced by more than one gene and linked to a maternal factor. In a study published in the American Journal of Human Genetics, an international collaborative team of researchers reports the finding of two genes that are associated with increased odds for women bearing fraternal twins.

“We know that dizygotic, or non-identical twins, is heritable and passed on down the maternal lineage. We had spent several years first identifying twinning genes in a really spectacular group of new world monkeys, the marmoset, who always have twins or triplets. Now we were ready to tackle the genetics of twinning in humans,” said Dr. Kjersti Aagaard associate professor of obstetrics and gynecology at Baylor College of Medicine and OB/GYN and maternal fetal medicine specialist at Texas Children’s Pavilion for Women, and one of the study’s lead authors. “Working with our colleagues around the globe, we not only found two genes with links to twinning, but to a number of different important signs of reproductive fitness.”

“There’s an enormous interest in twins and in why some women have twins while others don’t,” said Dr. Dorret Boomsma, a biological psychologist at Vrije Universiteit (VU), Amsterdam, and corresponding author for this work, who has compiled one of the largest twin databases in the world. “The question is very simple and our research shows for the first time that we can identify genetic variants [variations of a gene] that contribute to this likelihood.”

The follicle stimulating hormone (FSHB) gene, one of two genes found to be linked to DZ twinning, has shown significant effects on fertility affecting multiple reproductive aspects. For instance, FSHB helps control the menstrual cycle and the production of eggs by the ovary.

“We found that not only did the FSHB gene variant in moms associate with an increased likelihood of having DZ twins, but was associated in a gene dose-dependent manner to the amount of circulating follicle stimulating. In addition, women from four different cohorts around the globe carrying this genetic variant had their first period, menopause, their first child and their last child at an earlier age than women carrying other FSHB genetic variants,” said Aagaard.

Women who carried this FSHB genetic variant also showed signs of less occurrence of polycystic ovarian syndrome. With this discovery, researchers were able to tie this FSHB gene to multiple reproductive fitness traits.

The second gene found by the research team, SMAD3, affected the bearing of dizygotic twins a little differently.

“We found that moms who had this SMAD3 genetic variant also had a higher occurrence of twins,” said Aagaard. “But these moms were older at the birth of their last child, so it is a little bit different than what we saw with the FSHB variant.”

The SMAD3 genetic variant associated with DZ twinning, the authors propose, might increase the chances of DZ twinning by increasing the responsiveness to FSHB through the supporting granulosa cells.

Both genetic variants affect the growth of multiple follicles, which is needed for the development of non-identical twins. Dizygotic twins start with multiple ovulation, a maternal characteristic, and identical twins start with one embryo that splits in half.

This study focused on many different moms of twin cohorts from around the world, including a validation cohort of the population of Iceland. In this group, having each allelic FSHB variant increased women’s chances of having dizygotic twins by 18 percent per allele, and the SMAD3 variant increased the occurrence of twins by 9 percent per allele. Women who had both variants showed an increased chance of 29 percent.

The work has numerous potential applications in reproductive medicine and maternal health. For instance, it may help predict the outcome of multiple births and assist in the development of new strategies to optimize fertility.

Drawing on their recent work in the marmoset, Aagaard is optimistic that these and future evolution based genetic studies focused on twinning may yield key insights for pregnancy and reproductive health.

“What has always struck us about the marmoset is that their capacity for twinning is accompanied by unique adaptive traits that optimize their ability to both carry and care for multiple young at one time,” she said. “The more we can integrate our molecular and genetic findings in both marmoset and human moms, the greater the chance that we can unravel the mysteries of what enables reproductive fitness and optimal pregnancy outcomes in both singleton and multiple gestations.”

For the names, affiliations and support of the authors of this research, visit the Supplementary Materials section of the manuscript.

Research Finds Genes May Influence Leadership In The Workplace

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This article is courtesy of K-State News and Communications Services…..have thoughts about the article, please share in the comments section below…..

deskThe right genes may help you become an organization’s next president or CEO. But the same genes may also hinder your leadership path, according to Kansas State University psychological sciences research.

Wendong Li, assistant professor of psychological sciences in the College of Arts & Sciences, and collaborators have found a “mixed blessing” for workers who hold workplace leadership positions, from the formal leader of a CEO to an informal group leader. Their study focused on the dopamine transporter gene DAT1, which can influence leadership and is important for reward and motivation systems in humans.

“It’s like a mixed blessing — this gene can have both positive and negative effects on leadership,” Li said. “An implication is that it really depends on environmental factors to determine if overall it is a positive or negative.”

On the positive side, the researchers found that people who had the 10-repeat allele in the dopamine transporter were most likely to engage in adolescent mild rule-breaking behavior, which is positively associated with leadership, Li said. Such mild rule-breaking behavior may include actions such as skipping class, but it is not serious deviant behavior such as shooting.

“Mild rule-breaking is actually positively correlated with the chance for you to become a leader in adulthood,” Li said. “These kinds of behaviors can provide you with an advantage because they allow adolescents to explore boundaries and learn something new.”

On the negative side, the researchers found that people with the dopamine transporter gene scored lower on proactive personality, which can lead to positive changes at work and is important for leadership emergence.

“These people were less likely to regulate their own behaviors to make a positive change,” Li said. “It can be very difficult to make a positive change because it involves mobilizing resources to overcome difficulties and obstacles so that the change can happen. These people were not good at regulating behaviors such as being persistent.”

The takeaway from the study? To become a leader and be a good leader involves multiple factors — genes and the environment — working together, Li said. Some influential environmental factors — though not studied in this research — can include democratic parenting, a supportive family, and a challenging and cultivating workplace.

workdeskManagers cannot assume that changing one aspect of the work environment will be beneficial for all individuals, Li said, because employees bring individual characteristics to the organization. Some individual differences can’t be ignored because they are rooted in genetic makeup and enhance the chance for individuals to engage in certain types of behaviors, either positive or negative.

“In the long run, we are advocating more individualized and customized management practices, which allow people to choose the type of work environment that fits their individual characteristics,” Li said. “Customizing workplace practices is good for employee learning, development and leadership potential. Ultimately, it is good for employee performance and well-being, which in turn may enhance organizational effectiveness.”

The researchers used two sets of data for the study: The National University of Singapore’s Strabismus, Amblyopia, and Refractive Error Study, or STARS, which includes 309 people, and the National Longitudinal Study of Adolescent Health, which includes more than 13,000 individuals. The researchers had similar results with both samples, Li said.

The researchers recently published their research, “A mixed blessing? Dual mediating mechanisms in the relationship between dopamine transporter gene DAT1 and leadership role occupancy” in The Leadership Quarterly.

Genes And Obesity

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From Your Health Journal…..”If you have not heard of the Science Daily web site, I really encourage you to visit their page, as they have some fabulous articles, like the one in today’s review about Genes and Obesity: Fast Food Isn’t Only Culprit in Expanding Waistlines — DNA Is Also to Blame. Researchers at UCLA say it’s not just what you eat that makes those pants tighter — it’s also genetics. Many of us already know this, but it is very educational to read a story that explains it. In a study, researchers found that the amount of food consumed contributed only modestly to the degree of obesity. Research demonstrates that body-fat responses to high-fat, high-sugar diets have a very strong genetic component, and have identified several genetic factors potentially regulating these responses. The dramatic increase in obesity over the past few decades has been tightly associated with an increase in obesity-related conditions such as type 2 diabetes, heart disease and cancer. And while high-calorie diets containing high levels of fat and sugar, along with sedentary lifestyles, have been considered the most significant environmental factors contributing to this epidemic, the new UCLA research demonstrates that body-fat responses to food are strongly inherited and linked to our DNA. Please visit the Science Daily web site (link provide below) to read the full story. I love their site, and always try to draw traffic their way. So many amazing article.”

From the article…..

Researchers at UCLA say it’s not just what you eat that makes those pants tighter — it’s also genetics. In a new study, scientists discovered that body-fat responses to a typical fast-food diet are determined in large part by genetic factors, and they have identified several genes they say may control those responses.

The study is the first of its kind to detail metabolic responses to a high-fat, high-sugar diet in a large and diverse mouse population under defined environmental conditions, modeling closely what is likely to occur in human populations. The researchers found that the amount of food consumed contributed only modestly to the degree of obesity.

The findings are published Jan. 8 in the online edition of the journal Cell Metabolism and will appear Jan. 9 in the print version.

“Our research demonstrates that body-fat responses to high-fat, high-sugar diets have a very strong genetic component, and we have identified several genetic factors potentially regulating these responses,” said first author Dr. Brian Parks, a postdoctoral researcher at the David Geffen School of Medicine at UCLA. “We found that obesity has similar genetic signatures in mice and humans, indicating the mice are a highly relevant model system to study obesity. Overall, our work has broad implications concerning the genetic nature of obesity and weight gain.”

The dramatic increase in obesity over the past few decades has been tightly associated with an increase in obesity-related conditions such as type 2 diabetes, heart disease and cancer. And while high-calorie diets containing high levels of fat and sugar, along with sedentary lifestyles, have been considered the most significant environmental factors contributing to this epidemic, the new UCLA research demonstrates that body-fat responses to food are strongly inherited and linked to our DNA.

To read the full article…..Click here