Sec Chr And Determination

Question 1

Structure of sex chr

Answer 1

PAR1 and PAR2 at the end- which recombine

On
X- NPX-non pseudoautosomal of X
Y-MSY- male specific region of Y
Which don’t recombine

Question 2

Unisexual/gonochronic
Bisexual/hermaphrodites

Answer 2

Uni- male female diff
Bi- male female in one organism

Question 3

Types of chromosonal sex determination

Answer 3

XY- animals,fishes, flies

ZE- 🐦, 🐍, 🦋 male ZZ

XO- 🦗 male XO female XX

Haplodiploid sys- 🐝
Male unfertilized haploid egg
Female- diploid
Worker female- imperfect female
Queen- perfect female

Question 4

Environmental sex determination

Answer 4

Temp- in which egg incubated
🦎, 🐊 🐢
MF PATTERN- 🐢 LOW TEMP MALE
FM- tuatara -LOW TEMP FEMALE
FMFF- 🐊 LOW AND HIGH TEMP FEMALE, INTERMEDIATE - MALE
Temp that provide male=female- pivotal temp

imp emzyme- aromatase testosterone to estrogen
Low temp- low activity therefore male

pH
Social interaction
Seasonality

Question 5

Primary and secondary sex determination in mammals

Answer 5

Pri- presence of Y chr
Sec- hormones produced by gonads

Question 6

Formation of testes and ovary

Answer 6

Sex determining region(Sry) in Y gives rise to testes

Sry
Sox9- essential for sertoli cell differentiation- it produce anti mullerian hormone that supress female rep organ and give LEYDIG CELL
Fgf9- fibroblast growth factor9
Block beta catenin

When no Sry
Follicle cell- instead of sertoli cell
Theca cell- instead of leydig cell
Secret estrogen
Mullerian duct- female rep organs

Question 7

Which is default pathway - formation of testes or ovary

Answer 7

Ovary

Question 8

Sex determination of drosophila

Answer 8

Sex determination gene are present on autosomes

Sex switch direct female dev- Sxl (Xchr)
Activation of sxl relies on ratio of X chr to sets of autosomes

Female
2 sets of autosome+XX
Male
2 sets of autosome+XY - fertile
2 sets of autosome +X- sterile

Question 9

Gyandromorph

Answer 9

Organism on which certain region male, other female.
Arise dur to non disjunction/ chromosomal lagging during mitosis. Loss of X chr dusinf first mitosis in female
Have bilateral asymmetry
Eg drosophila

Question 10

Intersexes

Answer 10

Genetically similar throughout their body and are sterile

Question 11

Mosaicism

Answer 11

Cells within the same individual have different genetic makeup
Cause by - dna mutation, chromosomal abnormalities

Question 12

Chimera vs mosaic

Answer 12

Mosaic- 2 cell type from single zygote
Chimera- 2 or more zygote fused

Question 13

Can mosaicism passed to offspring

Answer 13

Yes if it’s germ line. If its somatic then no

Question 14

Sex determination in plants

Answer 14

Monomorphic - 1 plant have both sexes
In single flower- hermaphrodite
Diff flower- monoecious

Dioecious/polymorphic- unisexual- female and male plant

Question 15

Holandritic traits

Answer 15

Only found in males, due to gene plant in Y chr

Question 16

Pseudodominace in male

Answer 16

One 1 X chr is present therefore even if ots recessive it can determine phenotype
Males also known as hemizygous

Question 17

Sex limited traits

Answer 17

Genes present in both but expressed only in one sex (influenced by sex hormones). Mainly associated with secondary sexual chr.
Gene located on autosomes
Penetrance in one sex-0

Eg
Breast dev
Beard growth

Question 18

Sex influenced traist

Answer 18

also k/as sex comditioned trait
Trait present in both sexes but expression is different depending on the sex.
Dominant in one sex but recessive in other.
Gene localised on autosomes

Eg baldness - dominant in male

Question 19

Drosophila eye and sex

Answer 19

Female- red eye
Male- red and white

Question 20

Female homozygous/heterozygous
Male. Hemizygous

Match