Test 2: lecture 14 urogenital 2 Flashcards
Individual with congenital anatomical variations
such that the diagnosis of sex is confused.
intersex
intersex
Individual with congenital anatomical variations
such that the diagnosis of sex is confused.
Genital malformation occurs more frequently in males since many genes are required to take development in the ___.
male direction
Only ___of sex anomalies are due to chromosome aberrations or mutations to a known gene
<15%
Most sex anomalies are due to ___ or aberrant interactions between environmental and genetic factors.
new mutations
sex anomalies seems to be an increase incidence with ___
inbreeding.
genetic sex is based on
XY or XX
gonadal sex is based on
ovaries or testicles
phenotypic sex is based on
external sex organs
vulva vs prepuce
intersex can be classified in 4 types
Genetic sex (XX vs. XY)
Gonadal sex (ovaries vs. testicles)
Phenotypic sex (vulva vs. prepuce)
Behavioral sex
True hemaphrodite
phenotypic (outside sex organs) and gonadal sex doesn’t match
has male and female gonads
testes and ovaries or a combo
reported most frequently in swine, occasionally in dogs
pseudohermaphrodite
phenotypic and gonadal sex is different
gonad of only one sex (ovaries or testes)
occurs most frequently in goats, swine
most genetically female (XX)
may also be mosaic, chimeras
that has both ovarian and testicular tissue in it.
Ovatestis-organ
female pseudohermaphrodite can be produced by
exposure to exogenous androgens during embryonic life
Female pseudohermaphrodite - phenotypically resembles a male (penis) but has ovarian tissue.
Male Pseudohermaphrodite
Phenotypically resembles a
female (vulva) but has testicular tissue.
testicles most commonly in the abdominal cavity or beneath the skin in the scrotal region often an enlarged clitoris
term used for hermaphrodite in human medicine
differences of sex development
The Sex Chromosome DSD would include XXY, chimerism, XO variants, XY DSD and XX DSD.
5 ways for sex reversal
Mutation in SRY gene
Base pair substitution DNA-binding domain of SF1
Absence of functional WT1
Duplication or mutation of SOX9
Mutation in androgen receptors
Caprine Polled Intersex Syndrome
XX sex reversal in goats
The genetic sex is XX, but are male pseudohermaphrodites.
hypoplastic testes with Phenotypically female and have an enlarged clitoris, projecting vulva, hypoplastic vagina
dominant inheritance for the polled trait and recessive for sex-reversal.
inhibits forkhead box L2 FOXL2- which is needed for ovarian differentiation and follicle and oocyte maturation.
This problem can be prevented by being sure that either the sire or dam is horned
Previously thought that polled intersex regulated transcript 1 (PISRT1) was involved by repressing SOX9 which is a key regulator of testis differentiation. But research now supports that FOXL2 is solely responsible for this problem in goats
Mode of inheritance for CPI
Mode of inheritance
Dominant for polled trait
Recessive for sex-reversal
Genes affected
PISRT1-anti-testis factor represses SOX9 (key regulator of testis differentiation)
FOXL2-is needed for ovarian differentiation and follicle and oocyte maturation
How is FOXL2 gene changes in PIS goats
FOXL2 expression needed for ovarian differentiation and follicle and oocyte maturation.
In PIS goats the FOXL2 gene expression does not occur. So gonad becomes a testicle.
FOXL2 transcription initiates between 34 and 36 days of gestation in a subpopulation of somatic cells located in the deepest medulla of the XX gonad. This developmental stage corresponds to the gonadic switch i.e., the time point at which male determination is instructed by an increase of SRY→ SOX9 expression in the XY gonad.
how to prevent CPI
Caprine Polled Intersex Syndrome
only breed if sire or dam has horns
Hemopoietic Chimera
“Freemartin”
Female that developed in the same uterus with a male twin and has common blood supply
blastocysts fuse in the uterus about day 18 to 20 of gestation. By 28 days, the allantois chorion and blood vessels of the two placentas have anastomosed. occurs before sexual differentiation, which takes place around 40 to 50 days of gestation.
Males differentiate about 1 week earlier than females. Mullerian Inhibiting Factor produced by Sertoli cells adversely affects the development of the female genitalia. The gonads will be small and undifferentiated. The uterine tubes, uterus and cranial vagina (paramesonephric ducts) are inhibited and the mesonephric duct remnant (vesicular glands) are stimulated. The freemartin usually has female external genitalia but masculinization of the internal genitalia.
If the placentas and blood supply are separate, a normal female will develop (incidence 5-20% of heterosexual bovine twins).
XX/XY chimeras.
New diagnostic methods have improved sensitivity and are based on the detection of Y-chromosome DNA segments by polymerase chain reaction (PCR).
This is the most frequent form of intersexuality found in cattle. occasionally occur in other ruminants, sheep, goats, deer. Rare report in pigs and rhinoceros. freemartins produced when ewes carry 4 or more fetuses.
The male co-twin will also be XX/XY chimera. Great debate regarding reproductive effects in bull calves. Some concern that some bulls may have poorer semen quality.
80-95% of female calves born co-twin to a bull will be a ___. About 5-20% of those females may be normal.
freemartin
male freeman produce what that inhibit female development
Mullerian Inhibiting Factor produced by Sertoli cells adversely affects the development of the female genitalia.
ways to test for freemartin
test tube test
karyotype will be chimeric XX and XY
PCR tests for Y detection
characteristics of a freemartin
- Gonads are quite variable
- Female external genitalia- usually blind ended, coarse hair
- Undeveloped oviduct, uterus, vagina
- Seminal vesicles
In freemartin, The uterine tubes, uterus and cranial vagina (___) are inhibited and the ___remnant (vesicular glands) are stimulated.
paramesonephric ducts
mesonephric duct
economic value of freeman
Dairy – little value as the cannot conceive and lactate.
Beef - carcass value but cannot contribute to genetic gain of herd
Heat detection – estrous behavior when administered testosterone, estradiol or estrone