Gene duplication is an important source of phenotypic change and adaptive evolution. We use a novel genomic approach to identify highly identical sequence missing from the reference genome, ...confirming the cortical development gene Slit-Robo Rho GTPase activating protein 2 (
SRGAP2
) duplicated three times in humans. We show that the promoter and first nine exons of
SRGAP2
duplicated from 1q32.1 (
SRGAP2A
) to 1q21.1 (
SRGAP2B
) ~3.4 million years ago (mya). Two larger duplications later copied
SRGAP2B
to chromosome 1p12 (
SRGAP2C
) and to proximal 1q21.1 (
SRGAP2D
), ~2.4 and ~1 mya, respectively. Sequence and expression analysis shows
SRGAP2C
is the most likely duplicate to encode a functional protein and among the most fixed human-specific duplicate genes. Our data suggest a mechanism where incomplete duplication created a novel function —at birth, antagonizing parental
SRGAP2
function 2–3 mya a time corresponding to the transition from
Australopithecus
to
Homo
and the beginning of neocortex expansion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A contiguous gene syndrome due to deletions of the proximal short arm of chromosome 11 is described in eight patients belonging to four families. The main clinical features are multiple exostoses, ...enlarged parietal foramina, craniofacial dysostosis, and mental retardation. The patients have cytogenetic and/or molecular deletions of chromosome 11p11-p13. These deletions are located between the centromere and D11S914 in a region of approximately 20cM. The present study confirms the presence of a multiple exostoses gene on chromosome 11p. Furthermore, it suggests that the gene for isolated foramina parietalie permagna and genes associated with craniofacial dysostosis and mental retardation reside in the same chromosomal region.
This report provides an in-depth picture of similarities and differences in the professional and practice characteristics of women and men who are radiologists in the United States, with specific ...attention to whether gender differences are less pronounced among younger radiologists.
Data were taken from a national stratified random sample survey of radiologists. The response rate was 75%. The 1731 men and 294 women responding included diagnostic radiologists, radiation oncologists, and radiology-related nuclear medicine specialists.
Seven percent of respondents who completed their radiology residency before 1970 were women, compared with 9% in 1970-1979, 19% in 1980-1989, and 27% in 1990-1995. Gender differences were smaller among posttraining radiologists younger than 40 years old than among those 40 years old or older for the following questions: when the respondent decided to specialize in radiology, whether the respondent is a subspecialist within diagnostic radiology, whether the respondent's practice is primarily academic, whether the practice is privately owned, and whether the respondent is a practice owner (partner, shareholder). Women who were residents and fellows more frequently indicated problems with unwanted sexual attention occurring in the past 2 years than did women who were not in training positions. However, posttraining women were more likely to have encountered discrimination in salary, hiring, or promotion at some time in their careers.
Women's professional roles in radiology are changing slowly. A narrowing gender gap among younger radiologists on some professional and practice characteristics may indicate a further diminishing of gender differences in radiology in the future. It may also reflect greater gender equality at earlier rather than later stages of one's career.
To profile the demographic, professional, and practice characteristics of diagnostic radiologists and radiation oncologists in the United States.
Questionnaires mailed to a national stratified random ...sample of 3,024 diagnostic radiologists, radiation oncologists, and nuclear medicine specialists yielded a 75% response rate. Weighted data reflect what responses would be if all radiologists had been surveyed and had responded.
Among professionally active, posttraining radiologists in 1995, 14% were women; 12% were radiation oncologists, 62% diagnostic generalists, and 26% diagnostic subspecialists; 92% were board certified in radiology; 48% had postresidency fellowship training; 69% were in a position where practice ownership was a potential, and of these, 80% were practice owners. Enjoyment of work was less the greater the perceived effect of managed care on a radiologists practice, but average work satisfaction was unchanged from 1990. Among radiologists aged 55 years or older, the percentage who were retired was unchanged from 1990. Average hours worked by professionally active radiologists aged 65 years or older increased since 1990.
Despite the spread of managed care and other trends that affect radiologists, surprisingly, few changes were evident in the demographic or professional characteristics of U.S. radiologists in 1995 compared with 1990.
To determine what demographic, professional, and practice characteristics are related to the amount of time radiologists work per week, to their allocation of time among professional activities, and ...to their plans for retirement.
The American College of Radiology surveyed 2,804 radiologists and nuclear medicine specialists. Means and percentiles were calculated for the radiologists' number of hours and days worked per week, number of weeks away, percentage allocation of time, and retirement intentions. Multiple linear and logistic regression analyses were performed.
Full-time, post-training radiologists worked a mean of 50 hours per week. Radiologists spent 2 weeks on professional education and 4.4 weeks on vacation each year. On average, 68% of professional time was spent on hospital patient care; 18%, on office patient care; 7%, on teaching and research; and 5% on administration. Forty-one percent of radiologists planned to eventually work part-time; 47% intended to retire fully.
These data will provide an important baseline for modeling the future size of the radiologist workforce and for assessing changes in the ways radiologists use their time and plan their futures.
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