Tag Archives: chromosomes

Fertility: Sacrificing eggs for the greater good

A woman’s supply of eggs is a precious commodity because only a few hundred mature eggs can be produced throughout her lifetime and each must be as free as possible from genetic damage. Part of egg production involves a winnowing of the egg supply during fetal development, childhood and into adulthood down from a large starting pool. New research by Carnegie’s Alex Bortvin and postdoctoral fellow Safia Malki have gained new insights into the earliest stages of egg selection, which may have broad implications for women’s health and fertility. The work is reported in the early on-line edition of Developmental Cell. (more…)

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Selfish Gene may Undermine Genome Police

Biologists have been observing the “selfish” genetic entity segregation distorter (SD) in fruit flies for decades. Its story is a thriller among molecules, in which the SD gene destroys maturing sperm that have a rival chromosome. A new study reveals a tactic that gives SD’s villainy an extra edge.

PROVIDENCE, R.I. [Brown University] — For a bunch of inanimate chemical compounds, the nucleic and amino acids caught up in the infamous “selfish” segregation distorter (SD) saga have put on quite a soap opera for biologists since the phenomenon was discovered in fruit flies 50 years ago. A new study, a highlight in the March issue of the journal Genetics, provides the latest plot twist. (more…)

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Aging Cells Lose Their Grip on DNA Rogues

Transposable elements are mobile strands of DNA that insert themselves into chromosomes with mostly harmful consequences. Cells try to keep them locked down, but in a new study, Brown University researchers report that aging cells lose their ability to maintain this control. The result may be a further decline in the health of senescent cells and of the aging bodies they compose.

PROVIDENCE, R.I. [Brown University] — Even in our DNA there is no refuge from rogues that prey on the elderly. Parasitic strands of genetic material called transposable elements — transposons — lurk in our chromosomes, poised to wreak genomic havoc. Cells have evolved ways to defend themselves, but in a new study, Brown University researchers describe how cells lose this ability as they age, possibly resulting in a decline in their function and health. (more…)

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Better Way to Understand Plasmid Cloning from AddGene

Medical research has been studying molecular cloning for centuries. While many remember the Scottish lambs as the first successful cloning, there have been countless medical advances since then. Many of them are not as evident or dramatic as Molly the sheep, they have been blazing the trail for cloning vital organs, DNA strands and chromosomes in hopes of curtailing or even curing the maladies that plague the human race. Plasmids are at the forefront of this research in hopes they can learn how to insert DNA strands and restructure diseases or ailments on a molecular level.

It is difficult to describe what Plasmid is exactly. Plasmid is a biologically engineered DNA strands that are meant to be used in existing organisms as well as creating new ones. There are many aspects of it used in different ways from molecule cloning, manipulating genes or advancing medical research. Plasmids are circular fragments of double-stranded DNA. Plasmids are used in DNA strands and they can be replicated independently of original chromosomal DNA that created them. While they are mainly used for studying purposes at the moment in biological laboratories, they are meant to advance medical research and hopefully be used to prolong human life. (more…)

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Monkey Business: What Howler Monkeys Can Tell Us about the Role of Interbreeding in Human Evolution

ANN ARBOR — Did different species of early humans interbreed and produce offspring of mixed ancestry?

Recent genetic studies suggest that Neanderthals may have bred with anatomically modern humans tens of thousands of years ago in the Middle East, contributing to the modern human gene pool. But the findings are not universally accepted, and the fossil record has not helped to clarify the role of interbreeding, which is also known as hybridization.

Now a University of Michigan-led study of interbreeding between two species of modern-day howler monkeys in Mexico is shedding light on why it’s so difficult to confirm instances of hybridization among primates—including early humans—by relying on fossil remains. (more…)

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UCLA Scientists Discover How Key Enzyme Involved in Aging, Cancer Assembles

UCLA biochemists have mapped the structure of a key protein–RNA complex that is required for the assembly of telomerase, an enzyme important in both cancer and aging.

The researchers found that a region at the end of the p65 protein that includes a flexible tail is responsible for bending telomerase’s RNA backbone in order to create a scaffold for the assembly of other protein building blocks. Understanding this protein, which is found in a type of single-celled organism that lives in fresh water ponds, may help researchers predict the function of similar proteins in humans and other organisms. (more…)

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Offspring of Older Fathers May Live Longer

If your father and grandfather waited until they were older before having children, you might experience life-extending benefits. Biologists assume that a slow pace of aging requires that the body invest more resources in repairing cells and tissues.

A new study suggests that our bodies might increase these investments to slow the pace of aging if our father or grandfather waited until they were older before having children.

“If your father and grandfather were able to live and reproduce at a later age, this might predict that you yourself live in an environment that is somewhat similar — an environment with less accidental deaths or in which men are only able to find a partner at later ages,” said Dan T.A. Eisenberg, lead author of the study published June 11 in the Proceedings of the National Academy of Sciences. (more…)

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Timely Ends: Telomere Length in Early Life Predicts Lifespan

New research by a team from the Universities of Glasgow and Exeter shows that a good indicator of how long individuals will live can be obtained from early in life using the length of specialised pieces of DNA called telomeres.

Telomeres occur at the ends of the chromosomes, which contain our genetic code.

They function a bit like the plastic caps at the end of shoelaces by marking the chromosome ends and protecting them from various process that gradually cause the ends to be worn away. This method of DNA protection is the same for most animals and plants, including humans, and the eventual loss of the telomere cap is known to cause cells to malfunction. This study is the first in which telomere length has been measured repeatedly from early in life of an individual and then for the rest of their natural lives. The results show that telomere length in early life is strongly predictive of lifespan. (more…)

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