Connect 3 genetics

Choose all gametes produced by an XXY fruit fly.

- Y - X - XY - XX

Consider a testcross between a white-eyed male fruit fly and a heterozygous red-eyed female. The offspring are expected in what proportion?

1 red-eyed male : 1 white-eyed male : 1 red-eyed female : 1 white-eyed female

What ratio of offspring is expected from this cross of two Drosophila flies?

1 white-eyed male : 1 red-eyed female

Place these cells in the correct order in which they are formed during spermatogenesis, starting with the earliest at the top.

1. Spermatogonia 2. Primary Spermatocytes 3. Secondary spermatocytes 4. Spermatids 5. Sperm cells

How many autosomes do human sperm contain?

22

In his classical experiments with white-eyed fruit flies, Morgan obtained red-eyed F1 individuals by crossing white-eyed males with red-eyed (wild-type) females. When he crossed F1 males and females, he obtained an F2 generation with an overall ratio of _____.

3 (red-eyed individuals):1 (white-eyed individuals)

Meiosis of a primary spermatocyte results in how many spermatids?

4

What are the two cells produced during meiosis II in human females?

A large ovum and a smaller second polar body

Select the zygotes that can be formed from fertilization of an egg that is the abnormal product of nondisjunction of the sex chromosomes.

All Of The Following: - XXY - OY - XO - XXX

When you consider only the sex chromosomes, what types of gametes are produced by a female individual of a species with the XY system of sex determination?

All gametes carry a X chromosome.

One form of hereditary deafness is inherited with an X-linked recessive allele. What can be expected for the offspring of a deaf mother and a father with normal hearing?

All of the sons will be deaf and all of the daughters will have normal hearing.

Which species achieves dosage compensation by decreasing the level of expression on both X chromosomes in XX hermaphrodites to 50% relative to the single X of XO males?

Caenorhabditis elegans

What accounts for equal expression of genes on the sex chromosomes despite the fact that males and females have an unequal complement of sex chromosomes?

Dosage compensation

Which species achieves dosage compensation by increasing the expression of genes on the X chromosome in males by twofold?

Drosophila melanogaster

In humans, when does an oocyte complete meiosis I?

During ovulation

What explains the correlation between maternal age and meiotic segregational errors, such as those leading to trisomy 21 in humans?

Eggs do not complete meiosis I until ovulation occurs.

Color blindness is inherited with an X-linked recessive allele. Which term describes the genotype for a color-blind male?

Hemizygous

Hemophilia is inherited with an X-linked recessive allele. Which term describes the genotype for a male who has this blood-clotting disorder?

Hemizygous

What is the function of the SRY protein?

It activates testes development.

How does the risk of having a child with trisomy 21 change when a woman ages?

It increases

In terms of its sex, a _______ butterfly is designated as ZZ.

Male

Gametes, or sex cells, are produced by a process called __________.

Meiosis

Which statement accurately describes Y-linked genes in humans.

No Y-linked characteristics have been identified in humans besides those related to maleness, male viability, and sperm formation.

A female with Turner syndrome (XO) would have how many Barr bodies in her somatic cells?

None

A male with Klinefelter syndrome (XXY) would have how many Barr bodies in his somatic cells?

One

The end product of egg formation in humans is a large, nutrient-rich _______.

Ovum

In human oogenesis, the first meiotic division is asymmetrical and produces a secondary oocyte and a much smaller cell, known as a(n)

Polar Body

In human females, the _______ ________ are produced before birth. However, they enter a dormant stage at prophase of meiosis I, and remain there until the female becomes sexually mature.

Primary Oocytes

______ are produced from spermatogonia through mitosis.

Primary spermatocytes

Which genes on the X chromosome are able to escape the effects of X chromosome inactivation in female mammalian cells?

Pseudoautosomal (PAR) genes

When Morgan crossed a white-eyed female fly with a red-eyed male fly, the pattern seen in the progeny was crisscross inheritance. Select the phenotype of the progeny flies.

Red-eyed females and white-eyed males

In human XY embryos, the __________ protein activates development of embryonic testes which then secrete hormones that trigger the development of male sex organs.

SRY

During spermatogenesis, which of the following is the first to be haploid in number of chromosomes?

Secondary spermatocyte

Meiosis I of primary spermatocytes results in two _______ _________ .

Secondary spermatocytes

Based on how it is written, which of he following is a dominant mutant allele in Drosophila?

Ser

Chromosomes that differ between males and females are called _________ __________.

Sex chromosomes

Male-pattern baldness is an example of what kind of trait?

Sex-influenced

Which of the following statements accurately describes gametogenesis in sexually reproducing animals?

Specialized diploid cells divide by meiosis to produce haploid cells.

Male humans produce mature sperm by a process called ________ .

Spermatogenesis

Which statement about the X-0 system of sex determination seen in insects is true?

The male has one sex chromosome (the X) and is designated X0, whereas the female has a pair (two Xs).

Which of the following statements about the X-Y system of sex determination is true?

The male is XY and the female is XX.

In somatic cells of human females one of the two X chromosomes is randomly turned off. What is this mechanism called?

X-chromosome inactivation

_______ genes are those that are physically located on the X chromosome.

X-linked

What is the inheritance pattern for a trait that is more likely to occur in females and which is seen in every generation?

X-linked dominant

What is the inheritance pattern for a trait where all of the daughters and none of the sons of an affected male will be affected?

X-linked dominant

What is the inheritance pattern for a trait that generally affects more males than females and will never pass from father to son?

X-linked recessive

What is the inheritance pattern for a trait that more commonly affects males than females and can often be observed in brothers or fathers of a woman who has affected sons?

X-linked recessive

In the X-0 system of sex determination found in some moths, the male's chromosomes are listed as __________ , whereas the female's chromosomes are listed as ____________.

XO XX

In his large-scale crosses between red-eyed males and white-eyed females, Bridges observed a small proportion (about 1 in 2000) of white eyed female offspring which he determined to be XXY individuals. How did these individuals obtain their sex chromosomes?

XX from their mother, Y from their father

When Bridges performed large-scale crosses between red-eyed males and white-eyed females, he observed small numbers (about 1 in 2000) of white eyed female offspring. These flies were _____.

XXY

Which of the the following genotypes corresponds to a white-eyed male fruit fly?

XwY

Sex reversed females have ______.

a Y chromosome lacking a functional SRY gene

A fruit fly with the genotype XwXw is ____.

a white-eyed female

The germ line refers to _____.

all of the embryonic germ cells in an animal

In his classical experiment with white-eyed Drosophila flies, Thomas Hunt Morgan crossed red-eyed (wild-type) females with white-eyed males. He then crossed the red-eyed F1 generation fruit flies with each other and discovered that, while the F2 generation included both red-eyed and white-eyed individuals, ____.

all white-eyed individuals were male

The main product of oogenesis in humans is ____.

an ovum

In human males, primary spermatocytes undergo meiosis for the first time ____.

at puberty

The primary oocytes of a human female are formed ______, but are arrested in ______.

before birth; prophase I of meiosis

A member of the heterogametic sex ____.

can make two different types of gametes

When male flies inherit their eye color from their mother, and female flies inherit their eye color from their fathers, this is an example of _______ inheritance.

crisscross

In humans, primary oocytes are ____.

diploid

Despite the fact that human males are XY and human females are XX, they have equal expression of many genes on their sex chromosomes. This phenomenon is called _________ __________

dosage compensation

A diploid bee is _____.

female

In humans with a typical constitution of chromosomes, X-chromosome inactivation induces dosage compensation by randomly inactivating one of the X chromosomes in the somatic cells of ______.

females

A human oocyte completes meiosis II only if it is _____________

fertilized

A XXY fruit fly can make ____ types of gametes in terms of sex chromosome content.

four

At the end of meiosis during spermatogenesis in humans, each primary spermatocyte produces _____.

four haploid spermatids

In humans, secondary spermatocytes are produced _____.

from primary spermatocytes that undergo a symmetrical meiosis I

Hemophilia is an X-linked recessive trait. One of the conditions that must be met for a female child to have hemophilia is that ______.

her father must have hemophilia

In humans, the male is known as the________ sex, because males can make two types of gametes: one type of sperm carries only the X chromosome, and another type carries the Y chromosome.

heterogamete

Females ______ for an X-linked recessive trait can exhibit a patchwork pattern due to X-chromosome inactivation in early embryogenesis.

heterozygous

One form of hereditary deafness is inherited with an X-linked recessive allele. A woman with normal hearing has a son with hereditary deafness. The woman's genotype at this gene locus is ______.

heterozygous

Embryonic germ cells are collectively referred to as the germ _________.

line

Genes that are physically located on the X chromosome are called X- ________ genes.

linked

The presence of the SRY gene on the Y chromosome in mammals determines ______.

maleness

In mammals, the SRY gene on the Y chromosome determines ______, whereas lack of the SRY gene results in a ______ organism.

maleness, female

Bridges observed that in a cross between white-eyed females and red-eyed males, the majority of the progeny were red-eyed females and white-eyed males. However, a very small number of males had red eyes, and females had white eyes. Bridges proposed this was due to ______ in meiosis.

nondisjunction

To prove that the SRY gene determines maleness, scientists placed the SRY gene

on an autosome in an XX mouse.

Human females produce egg cells by a process called _________

oogenesis

Oogenesis in humans takes place in the ______.

ovaries

Random X-chromosome inactivation in early embryogenesis leads to _____.

patchwork females

During oogenesis in humans, cells called ___________ ___________ are formed from oogonia and undergo meiosis to ultimately form an ovum.

primary oocytes

Spermatogonia undergo mitosis to produce _________

primary spermatocytes

The existence of XX males and XY females is called sex _______

reversal

A trait that is found in both sexes, but exhibits different expression, perhaps due to hormonal differences, is a(n) _________-________ trait.

sex - influenced

Chromosomes that differ in size and composition between males and females are called ______.

sex chromosomes

A phenomenon involving animals of the same species, but of opposite sexes, that have different physical features is called ________ _________.

sexual dimorphism

Male birds often have more ornate and colorful feathering patterns than female birds. This is an example of ______.

sexual dimorphism

Y-linked traits would pass from an affected father to all of his________ , and none of his _________.

sons daughters

Sperm are formed when __________ mature by developing a whiplike tail and concentrating all of their chromosomal material in the head.

spermatids

Spermatogenesis takes place in the ______.

testes

A trait that a son can inherit only from his mother must be due to an allele found on ______.

the X chromosome

When a daughter can inherit a sex-linked allele from either her mother or father, it must be located on ______.

the X chromosome

In Drosophila, genes are typically named based on _____.

the mutant phenotype that revealed their existence

A human male with Klinefelter syndrome (XXY) has _____.

three doses of the genes in the PAR regions

Color blindness is due to an X-linked recessive allele. To be color blind, females must inherit ______ copy(ies) of this allele and males must inherit ______ copy(ies).

two; one

In human males, spermatogenesis takes ___.

up to two months

When scientists added an SRY transgene to the genome of XX mice, the mice _____.

were phenotypically male