Genetics Chapter 5

Select all of these that are influenced by maternal effect gene products. -Cell division -Fertilization -Cleavage pattern -Body axis orientation -Oogenesis

-Cell division -Cleavage pattern -Body axis orientation

Extranuclear genes are not segregated into gametes the same way the nuclear chromosomes are. As such, extranuclear genes ______ exhibit Mendelian patterns of inheritance. -do not -do

-do not

In a somatic cell, the genomic imprint is _____. -permanent -temporary

-permanent

True or false: The genes located in mitochondria and chloroplasts do not exhibit Mendelian patterns of inheritance.

True Reason: Extranuclear genes are not segregated into gametes the same way the nuclear chromosomes are. As such, extranuclear genes do not exhibit Mendelian patterns of inheritance.

In a mitochondrion, genetic material is located in a region called the _____.

nucleoid

A female with Turner syndrome (XO) would have how many Barr bodies in her cells? -One -Three -None -Two

-None

A person who has somatic cells with two Barr bodies could have which of the following genotypes? -XXXY -XXY -XYY -XXX -XO

-XXXY -XXX

What is a Barr body? -An inactivated X chromosome in mammalian somatic cells -An inactivated autosome in mammalian somatic cells -An inactivated Y chromosome in mammalian somatic cells

-An inactivated X chromosome in mammalian somatic cells

Select characteristics of mitochondrial DNA mutations. -Mitochondrial DNA mutations are only inherited from the father. -Mitochondrial DNA mutations are transmitted from a mother only to her male offspring. -Mitochondrial DNA mutations are only found in gamete-forming cells, not in somatic cells. -Mitochondrial DNA mutations may occur in somatic cells and accumulate as a person ages. -Mitochondrial DNA mutations are transmitted from a mother to all of her offspring.

-Mitochondrial DNA mutations may occur in somatic cells and accumulate as a person ages. -Mitochondrial DNA mutations are transmitted from a mother to all of her offspring.

Variegation, a condition in which a leaf will have a mixture of normal and mutant chloroplasts (as shown), is a condition known as _____.

heteroplasmy

In chloroplasts, DNA is found in regions called ____.

nucleoid

Genes located on chromosomes are called nuclear genes because they are located in the cell ____.

nucleus

What is genomic imprinting? -A form of epigenetic inheritance in which a segment of DNA is marked in a way that it alters gene expression -The expression of genes based on inheritance through the cytoplasm of the egg -The inactivation of an X chromosome by Xist gene RNAs -A form of inheritance in which organellar genetic material influences gene expression

-A form of epigenetic inheritance in which a segment of DNA is marked in a way that it alters gene expression Reason: Genomic imprinting refers to a situation in which a segment of DNA is marked before fertilization, and that mark is retained and recognized throughout the life of the organism inheriting the marked DNA.

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? -Sex influenced inheritance -Sex limited inheritance -Dosage compensation -Maternal effect

-Dosage compensation

Which inheritance pattern is typical of the transmission of mutations in mitochondrial DNA in humans? -From the mother to her daughters only -From the mother to her sons only -From the father to his sons only -From the father to his daughters only -From the father to all of his offspring -From the mother to all of her offspring

-From the mother to all of her offspring

Which of these are examples of extranuclear genes? -Genes located on a chromosome in a mitochondrion -Genes located on a chromosome in a chloroplast -Genes located on a chromosome in the nucleus

-Genes located on a chromosome in a mitochondrion -Genes located on a chromosome in a chloroplast

(Image in text)A male and a female offspring each have an unmethylated maternal chromosome (purple), and a methylated paternal chromosome (blue). The same methylation pattern occurs in all somatic cells due to maintenance methylation. However, demethylation occurs in cells destined to become gametes. In the early oocyte, no methylation occurs, ultimately leading to eggs with either the original maternal (purple) or paternal (blue) chromosome, both of which are unmethylated. In the early spermatocyte, both chromosomes are similarly unmethylated, but de novo methylation occurs on both chromosomes prior to the formation of gametes. Therefore, sperm are formed which have either the original maternal (purple) or paternal (blue) chromosome, both of which are methylated. Based on the information in the figure,will the paternal or maternal chromosome be active in the resulting zygote? -Maternal -Paternal

-Maternal Reason: The DNA in the sperm has been imprinted by DNA methylation and will therefore be silenced.

What type of inheritance accounts for the genotype of the mother being the direct determining factor in the phenotype of the offspring? -Maternal effect -X-linked inheritance -Paternal effect -Sex influenced effect -Codominance

-Maternal effect

If the expression of genes in the offspring directly influences their traits, the genes are transmissible from generation to generation, the genes segregate during gamete formation, and the genes of the trait segregate independently, then the genes follow ______ inheritance patterns. -non-Mendelian -Mendelian

-Mendelian

The mice in the figure are heterozygous, Igf2 Igf2-, yet they have different phenotypes due to genomic imprinting. What is this phenomenon called? -Incomplete dominance -Monoallelic expression -Codominance -Variable expression

-Monoallelic expression

Which genes on the X chromosome are able to escape the effects of X chromosome inactivation in female mammalian cells? -FoxP3 gene -Paternal effect genes -Pseudoautosomal genes -SRY gene -AZF1 gene

-Pseudoautosomal genes

Select all of these that are true of genes that follow a Mendelian inheritance pattern. -The genes are transmissible from generation to generation. -Expression of genes in the offspring directly influences their traits. -The genes are influenced by expression of maternal genes in the egg. -The genes segregate during gamete formation. -The genes segregate independently.

-The genes are transmissible from generation to generation. -Expression of genes in the offspring directly influences their traits. -The genes segregate during gamete formation. -The genes segregate independently.

Select all of the true statements regarding genomic imprinting. -Genomic imprinting is temporary in somatic cells. -The marking of alleles can be altered from generation to generation. -Genomic imprinting is permanent in somatic cells. -The marking of alleles cannot be altered from generation to generation.

-The marking of alleles can be altered from generation to generation. -Genomic imprinting is permanent in somatic cells.

Which statements regarding nucleoid structure of mitochondria and chloroplasts are true? -The genome is a circular. -There will always be a single nucleoid per organelle. -The genome is linear. -There may be more than one chromosome in the nucleoid. -There may be more than one nucleoid per organelle. -The genome consists of double-stranded DNA.

-There may be more than one chromosome in the nucleoid. -There may be more than one nucleoid per organelle. -The genome consists of double-stranded DNA. -The genome is a circular.

The genome located in the nucleoid of a mitochondrion or chloroplast consists of a ______ chromosome. -linear, single-stranded RNA -linear, double-stranded DNA -circular, single-stranded RNA -circular, double-stranded DNA

-circular, double-stranded DNA

Which statements regarding genomic imprinting are true? Genomic imprinting ______. -occurs in several species including insects, mammals, and flowering plants -only involves a single gene -only occurs in placental and marsupial mammals -determines X-chromosome inactivation in marsupials -may involve a single gene, a part of a chromosome or the entire chromosome

-determines X-chromosome inactivation in marsupials (Reason: In marsupials, XCI is not random; the maternal X is always active.) -may involve a single gene, a part of a chromosome or the entire chromosome -occurs in several species including insects, mammals, and flowering plants

(Image in text) A male and a female offspring each have an unmethylated maternal chromosome (purple), and a methylated paternal chromosome (blue). The same methylation pattern occurs in all somatic cells due to maintenance methylation. However, demethylation occurs in cells destined to become gametes. In the early oocyte, no methylation occurs, ultimately leading to eggs with either the original maternal (purple) or paternal (blue) chromosome, both of which are unmethylated. In the early spermatocyte, both chromosomes are similarly unmethylated, but de novo methylation occurs on both chromosomes prior to the formation of gametes. Therefore, sperm are formed which have either the original maternal (purple) or paternal (blue) chromosome, both of which are methylated. As seen in the figure, de novo methylation of a gene or chromosome occurs in ______. -somatic cells -gametes

-gametes

(Image in text) Illustration shows a leaf which has a condition of variegation. It has mixture of mutant and normal chloroplast. In this, plant formed from a fertillized egg has both types of chloroplast. This is called heteroplasmy. The variegation of the leaf shown in the image can be explained by ______. -X-chromosome inactivation -Mendelian inheritance -heteroplasmy -paternal leakage

-heteroplasmy

The inactivated X chromosome in somatic cells of mammals, like the one shown by the arrow in this image, is called a ____.

Barr Body

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 _____.

Blank 1: dosage, dosage compensation, X-chromosome, X, or dose Blank 2: compensation or inactivation

True or false: Epigenetic changes to a chromosome are permanent modifications that remain over the lifetime and later generations of the organism.

False Reason: Epigenetic changes to a chromosome modify the chromosome during oogenesis, spermatogenesis or embryogenesis, but are not permanent over the course of many generations.

True or false: All genes on the inactivated X chromosome remain inactivated throughout life in a somatic cell of an adult female. True false question.

False Reason: some genes on the inactivated X chromosome are expressed in the somatic cells of adult female mammals

True or false: In Drosophila, proper anteroposterior and dorsoventral development requires a separate set of maternal effect gene products accumulating in the appropriate area of the embryo.

True Reason: Studies in Drosophila, mice and humans have identified several maternal effect genes that are required for proper development.

A pattern of inheritance in which a temporary alteration to a chromosome modifies gene expression but is not permanent over many generations is called _____ inheritance.

epigenetic or epigenetics

In a form of epigenetic inheritance called _______, a segment of nuclear DNA is marked in a non-permanent way that alters gene expression throughout the life of the individual.

genomic imprinting

In an inheritance pattern called _____, the genotype of the mother directly determines the phenotype of her offspring for a given gene.

maternal effect