Friday Five #10: Chimps, Heart Disease, and your future career

1) Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content: You had to be on Mars to miss this one this week. An article appeared in Nature that demonstrated that the Y-chromosome between Chimps and Humans was highly divergent, on the lines of 310 millions years so there is more similarity between chickens and human males (may explain my inexplicable desire to look like Colonel Sanders) then between chimps and humans. Here is the abstract.

The human Y chromosome began to evolve from an autosome hundreds of millions of years ago, acquiring a sex-determining function and undergoing a series of inversions that suppressed crossing over with the X chromosome^{1, 2}. Little is known about the recent evolution of the Y chromosome because only the human Y chromosome has been fully sequenced. Prevailing theories hold that Y chromosomes evolve by gene loss, the pace of which slows over time, eventually leading to a paucity of genes, and stasis^{3, 4}. These theories have been buttressed by partial sequence data from newly emergent plant and animal Y chromosomes^{5, 6, 7, 8}, but they have not been tested in older, highly evolved Y chromosomes such as that of humans. Here we finished sequencing of the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY. By comparing the MSYs of the two species we show that they differ radically in sequence structure and gene content, indicating rapid evolution during the past 6 million years. The chimpanzee MSY contains twice as many massive palindromes as the human MSY, yet it has lost large fractions of the MSY protein-coding genes and gene families present in the last common ancestor. We suggest that the extraordinary divergence of the chimpanzee and human MSYs was driven by four synergistic factors: the prominent role of the MSY in sperm production, ‘genetic hitchhiking’ effects in the absence of meiotic crossing over, frequent ectopic recombination within the MSY, and species differences in mating behaviour. Although genetic decay may be the principal dynamic in the evolution of newly emergent Y chromosomes, wholesale renovation is the paramount theme in the continuing evolution of chimpanzee, human and perhaps other older MSYs.

2) Telomere Length Trajectory and Its Determinants in Persons with Coronary Artery Disease: Longitudinal Findings from the Heart and Soul Study A good study that looks at telomere length and risk of cardiovascular disease. Telomeres are a good indicator of biological aging. They are basically the ends of chromosomes and as you age and the body replenishes cells through meiosis they begin to degrade.

Background

Leukocyte telomere length, an emerging marker of biological age, has been shown to predict cardiovascular morbidity and mortality. However, the natural history of telomere length in patients with coronary artery disease has not been studied. We sought to investigate the longitudinal trajectory of telomere length, and to identify the independent predictors of telomere shortening, in persons with coronary artery disease.

Methodology/Principal Findings

In a prospective cohort study of 608 individuals with stable coronary artery disease, we measured leukocyte telomere length at baseline, and again after five years of follow-up. We used multivariable linear and logistic regression models to identify the independent predictors of leukocyte telomere trajectory. Baseline and follow-up telomere lengths were normally distributed. Mean telomere length decreased by 42 base pairs per year (p<0.001). increase =" 7.6;" years =" 1.6;" or =" 2.4;" increase =" 1.4;">

Conclusions/Significance

Leukocyte telomere length may increase as well as decrease in persons with coronary artery disease. Telomere length trajectory is powerfully influenced by baseline telomere length, possibly suggesting negative feedback regulation. Age, male sex, and abdominal obesity independently predict telomere shortening. The mechanisms and reversibility of telomeric aging in cardiovascular disease deserve further study.

3) 'Missing Link' Between Heart Failure and Environment Discovered : Similiar to the article above, this looks at the link between DNA methlyation and heart failure. Throughout most of your life certain genes or portions of genes that are not supposed to be copied are halted through methalyation or they are told you are a heart muscle cell - please stay a heart muscle cell. This is an interesting study as it indicates epigeneitic (an overused buzz word that sounds smarter than envionment).

4) U.S. Adult Obesity Still High, but Recent Data Suggest Rates May Have Stabilized A news item that mentions that obesity is still very high in the US but it seems to have stabilized, but of course this could go either way.

5) Future jobs: what might you be doing? What do you want to be in the future. Here I was hoping to do be sitting in the lab of luxury, pushing buttons ala George Jetson.