Sex Determination

Question 1

• Observed in most snakes and lizards

- sex is determined by the temperature of incubation during development

Answer 1

Temperature dependent sex Determination

Question 2

Sex determination: there is only one male in every fish school, primary male. Animal?

Answer 2

Blue headed wrasse

Question 3

In blue headed wrasse, if male dies largest female become a male, ovaries shrink and testes grow. ______ male. If a new male fish joins a school that already has male present, the newcomer male becomes a female (yellow).

Answer 3

Terminal

Question 4

Blue headed wrasse: female is color _____, primary male is _____, terminal male ______

Answer 4

Yellow, blue, blue head, yellow/green body

Question 5

Marine mollusk that begins in life as a swimming larva, then settle on a solid substrate to become an adult. ________ live in stacks on top of another

Answer 5

Slipper limpets- Crepidula fornicata

Question 6

Platypus have ____ sex chromosomes

Answer 6

10

Question 7

• produces like gametes
• all gametes produced have an X chromosome
• females in human and Drosophila (XX)
• males in butterflies and most birds

Answer 7

Homogametic sex

Question 8

• produces unlike gametes
• produces gametes with an X chromosome and gametes without and X chromosome
• diploid can be either XY or X0
• females in butterflies and most birds

Answer 8

Heterogametic sex

Question 9

Lygaeus mode is

Answer 9

XX/XY

Question 10

Protenor mode is

Answer 10

XX/XO

Question 11

X and Y chromosomes are homologous only at ______ regions

Answer 11

Pseudo autosomal

Question 12

Syndrome?-47 chromosomes, XXY. Y is sufficient to cause maleness in an individual with two X’s

Answer 12

Klinefelter syndrome

Question 13

Syndrome?- 45 chromosomes. X. Absence of Y results in femaleness, even if only one X is present

Answer 13

Turner syndrome

Question 14

Are visible during interphase. All X chromosome, except one, are inactivated. Result: dosage compensation

Answer 14

Barr bodies

Question 15

Occur at random early during development. Once inactivation has occurred, all progenies from each cell will have the same X chromosome inactivated. Females are mosaics for all heterozygous X linked loci. Normal males do not exhibit these patterns. Examples are:

Answer 15

Inactivation of X chromosomes. Tortoiseshell or calico- XOXB

Question 16

• X linked disorder
• males lack swear glands
• the skins of heterozygous females are mosaics

Answer 16

Anhidrotic ectodermal dysplasia

Question 17

Primary sex determination in humans is _____. These genotypes are ____ or _____

Answer 17

Chromosomal. XX or XY.

Question 18

Secondary determination is humans is _____. Bring distinguishing features of the sexual phenotype other than the gonads

Answer 18

Hormonal.

Question 19

All humans regardless of chromosomal genotype, develop _____ ____ that can become either testes or ovaries.

Answer 19

Bipotential gonads

Question 20

Bipotential gonads begin to develop at week ____ and remain sexually indifferent until week ____, when they develop into either testes or ovaries

Answer 20

4, 7

Question 21

Gonads are primary sexual _____

Answer 21

Characters

Question 22

In human Y chromosomes, the remaining 95% is

Answer 22

Male specific region of Y

Question 23

Human Y chromosome: the gene that controls the male sexual development

Answer 23

Sex determining region of Y

Question 24

Human Y chromosome: induces the sexually indifferent gonads to become testes

Answer 24

Testis-determining factor

Question 25

During organogenesis ...

Answer 25

Secondary sexual determination and sexual differentiation

Question 26

During early adolescence, further sexual determination and production of active gametes following an increase in production of _______ hormones

Answer 26

Gonadal

Question 27

XY individuals, testes develop, testes produce male hormones BUT the target tissue do not respond to these hormones, estrogen from the adrenal glands direct feminization, result in all female secondary sexual characters

Answer 27

Androgen insensitivity syndrome

Question 28

Human females have 2 X chromosomes, so they may be either ____ or ____ for any X locus

Answer 28

Homozygous or heterozygous

Question 29

Humans makes have only one X chromosome, so they are _____ for all X loci

Answer 29

Hemizygous

Question 30

Normal males always express the phenotypes associated with _____ alleles

Answer 30

X-linked