Exam 2 - Chapter 7: Sexual Inheritance

Question 1

What does homogametic mean?

Answer 1

two of the same type of chromosome; typically referring to sex chromosomes

Question 2

What does heterogametic mean?

Answer 2

two different types of a chromosome: typically referring to sex chromosomes

Question 3

What does hemizygous mean?

Answer 3

Only one copy of a gene

Question 4

What is sperm in reference to number of sex chromosomes?

Answer 4

hemizygous

Question 5

What are autosomes?

Answer 5

Non sex determining chromosomes

Question 6

What are sex chromosomes?

Answer 6

Chromosomes that differ in males and females and determine sex

Question 7

What is sexual dimorphism?

Answer 7

Difference in appearance or characteristics between sexes of the same species

Question 8

What is a karyotype?

Answer 8

visual representation of an individuals chromosomes in an organized format

Question 9

What is x-linked inheritance?

Answer 9

When a gene is only located on the X sex chromosomes and not Y

Question 10

What is criss cross inheritance?

Answer 10

A trait is passed from one sex to the opposite sex and then to the next generation

Question 11

What typically causes criss-cross inheritance?

Answer 11

X-linked inheritance

Question 12

What is pseudoautosomal inertitance?

Answer 12

Gene is bound on both X and Y chromosome so inheritance acts like autosomal

Question 13

What is Holandric inheritance?

Answer 13

Y-linked inheritance

Question 14

What is Y-inheritance and how does it manifest in generations?

Answer 14

Gene found of Y chromosome and does not skip generations

Question 15

What are sex-limited traits?

Answer 15

gene is located on autosomal chromosome but expression is influenced by sex chromosomes

Question 16

What is X chromosome nondisjunction?

Answer 16

when meiosis I produces an ovum with two X chromosomes and an ovum with no X chromosomes

Question 17

How does nondisjunction in meiosis I affect gametes?

Answer 17

One gamete with both homologs and one with neither before meiosis II occurs

Question 18

How does non-disjunction in meiosis II affect gametes?

Answer 18

One gamete is contains 2 sister chromatids and one contains neither

Question 19

What does Sry stand for?

Answer 19

Sex-determining region Y

Question 20

What is the Sry and its function?

Answer 20

A gene of the Y chromosome that encodes for protein testis-determining factor (TSD)

Question 21

What is the function of testis-determining factor?

Answer 21

testis differentiation and male sexual development

Question 22

What does XXY result in?

Answer 22

Male sexual development

Question 23

What does XO result in?

Answer 23

Female sexual development

Question 24

What does Sxl stand for and what organism does it exist in?

Answer 24

sex lethal gene; drosophila

Question 25

What chromosome is Sxl located on?

Answer 25

X chromosome

Question 26

What occurs if the Sxl is deleted?

Answer 26

XX develop as males but die, XO is unaffected and develop as males

Question 27

What occurs in XX embryos if Sxl gene is present?

Answer 27

Triggers dsx gene to express female isoform

Question 28

What occurs in X embryos if Sxl is present?

Answer 28

Sxl gene is not turned on and dsx gene exists as male isoform; X is hypertranscribed

Question 29

What is ratio based sex determination?

Answer 29

What sex is determined by ration of sex chromosomes rather than presence of a specific sex chromosome

Question 30

How does mosaicism occur by influencing XXY?

Answer 30

Miotic descents of original XXY cell lose either X or Y and subsequent cells in the area develop without the chromosome

Question 31

What is a ZZ sex chromosome combination mean?

Answer 31

Male in birds

Question 32

What is a ZW sex chromosome combination mean?

Answer 32

female in birds

Question 33

What is a mating type?

Answer 33

A gene with two alleles that determine sex; allele based sex determination

Question 34

What is haplodiploid?

Answer 34

When one sex is haploid and the other is diploid

Question 35

What kind of sex determination is haplodiploidy?

Answer 35

Allele based

Question 36

What is paternal genome elimination?

Answer 36

both parental genomes are used to fertilize offspring and produce a zygote, but males genome is eliminated after

Question 37

What is parthogenesis?

Answer 37

reproduction where ovum receives full diploid genome from a single parent and passes it on the offspring; no outside fertilization needed

Question 38

What is environmental sex determination?

Answer 38

Sex is determined by environmental signal during development

Question 39

What is dosage compensation in sex chromosomes?

Answer 39

controlling levels of expression of sex-linked genes based on the sex of the individual or number of sex chromosomes

Question 40

What is the dosage compensation complex (DCC)?

Answer 40

complex of protein and RNA recruited to X-chromosome is responsible for increasing transcription of X-linked genes

Question 41

How many sex chromosomes are transcribed in mammals?

Answer 41

Only one X in females and males

Question 42

What is a Barr body or sex chromatin body?

Answer 42

A chromosome that has been condensed into heterochromatin and localized to the nuclear membrane so it is not transcribed

Question 43

How is one of the X chromosomes in female mammals inactivated?

Answer 43

It is transformed into a Barr body

Question 44

How does calico pattern in cats result?

Answer 44

Different X chromosomes are turned into Barr bodies in different parts of the body

Question 45

What is a Xist?

Answer 45

A huge piece of RNA that helps shut down a chromosome is resides in and contributes to making Barr bodies