sex determination


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determination

 [de-ter″mĭ-na´shun]
the establishment of the exact nature of an entity or event.
embryonic determination the loss of pluripotentiality in any embryonic part and its start on the way to an unalterable fate.
sex determination the process by which the sex of an organism is fixed; associated, in man, with the presence or absence of the Y chromosome.

sex de·ter·mi·na·tion

determination of the sex of a fetus in utero by identification of fetal chromosomes.

sex determination

Etymology: L, sexus, sex, determinare
the process of identifying the sex of an individual on the basis of the presence of the XY chromosome combination in the cells of genetic males or Barr bodies in the cells of genetic females or of secondary sexual characteristics and skeletal variations.
The mechanism in a given species by which sex is determined. In many species, it is determined at the time of fertilisation by the characteristics of the sperm fertilising the egg

sex de·ter·mi·na·tion

(seks dĕ-tĕr'mi-nā'shŭn)
1. Identification of the sex of a fetus in utero by identification of fetal chromosomes or by imaging of physical appearance of external genitalia.
2. The determination of the gender of a preimplanted embryo during in vitro fertilization.

sex determination

the control of maleness and femaleness by genes located on SEX CHROMOSOMES. The actual mechanism differs in various organisms but very often is through a HETEROGAMETIC SEX and a

sex

1. the fundamental distinction, found in most species of animals and plants, based on the type of gametes produced by the individual or the category to which the individual fits on the basis of that criterion. Ova, or macrogametes, are produced by the female, and spermatozoa, or microgametes, are produced by the male. The union of these distinctive germ cells results in the production of a new individual in sexual reproduction.
2. to determine the sex of an animal.

sex cell
see germ cell, gamete.
sex chromatin
the persistent mass of chromatin situated at the periphery of the nucleus in cells of normal females; it is the material of the inactivated sex chromosome. Called also Barr body.
chromosomal sex
sex as determined by the presence of the XX (female) or the XY (male) genotype in somatic cells, without regard to phenotypic manifestations. Called also genetic sex.
sex chromosomes
see sex chromosomes.
sex determination
1. the change in the fetus to a male or female configuration; the process by which the sex of an organism is fixed, associated, in animals, with the presence or absence of the Y chromosome.
2. diagnosis of the sex of the fetus before birth performed by examination of fetal fluids obtained by amniocentesis.
sex determining region of Y
a single gene responsible for determining the sex of an animal.
sex drive
see libido.
endocrinological sex
the phenotypic manifestations of sex determined by endocrine influences, such as mammary development, etc.
genetic sex
chromosomal sex.
sex glands
in the male includes the prostate, seminal vesicles, ampullae and bulbourethral glands; in the female includes ovaries.
gonadal sex
the sex as determined on the basis of the gonadal tissue present (ovarian or testicular).
sex hormones
glandular secretions involved in the regulation of sexual functions. The principal sex hormone in the male is testosterone, produced by the testes. In the female the principal sex hormones are the estrogens and progesterone, produced by the ovaries.
These hormones influence the secondary sex characters, such as the shape and contour of the body and head, mammary development and the pitch of the voice. The male hormones stimulate production of spermatozoa, and the female hormones control ovulation, pregnancy and the estral cycle.
sex-linkage
includes X-linked (much the most common) and Y-linked loci.
sex-linked inheritance
see sex-linkage (above).
morphological sex
sex determined on the basis of the morphology of the external genitals.
neutrophil sex lobe
see drumstick lobe.
nuclear sex
the sex as determined on the basis of the presence or absence of sex chromatin in somatic cells, its presence normally indicating the XX (female) genotype, and its absence the XY (male) genotype.
sex parity
see sex ratio (below).
sex pheromone
sex ratio
proportion of female to male births.
sex reversal
the sexual condition of animals in which gonadal sex and chromosomal sex are dissimilar.
sex steroids
steroidal compounds acting as hormones in reproductive processes; the principal ones are estrogen, progesterone, testosterone.
References in periodicals archive ?
In addition to its role in sex determination, the X chromosome is also predicted to become evolutionarily specialised for spermatogenesis.
Biologists have already recognized that control of sex determination has switched back and forth between genetics and the environment over the course of lizard evolution.
All 19 respondents were aware that the PCPNDT Act was enacted to prevent sex determination.
Here she highlights the importance of the Australian researcher Jennifer Graves' adoption of an explicitly feminist theoretical framework, her introduction of gender criticism to the field of sex determination genetics, and her disputes with the American geneticist David Page.
Sex determination of Red-tailed Hawks (Buteo jamaicensis calurus) using DNA analysis and morphometries.
Where a female places her eggs can influence the risk of predation on the nest, hatching success, and sex ratios within the nests of species that exhibit temperature-dependent sex determination (Schwarzkopf and Brooks, 1987; Janzen, 1994; Wilson, 1998; Kolbe and Janzen, 2002; Spencer and Thompson, 2003).
Traditionally, constant temperatures have been used when examining the relationship between incubation temperature and sex in turtles exhibiting temperature-dependent sex determination (TSD).
Officials also inform that sex determination of newborns though illegal in the state but are openly practiced and if the family comes to know that it's a girl child such negligence is common practice.
Thus, it has been pointed out that the proportion of boys among the new born babies is increasing sharply and it is commonly assumed to be the result of the rapid spread of the use of ultrasound and amniocentesis for sex determination and subsequent sex-selective induced abortions.
It shows that practice of sex determination is more common in the civilized areas of the state.