Chapter 5- Non Mendelian Inheritance

How many Barr bodies would an individual with a XXY genotype possess?

1

A man with Prader-Willi syndrome has children with a woman that has Angelman syndrome what is the expected ratio of progeny?

1 Prader-Willi : 1 Angelman : 1 normal : 1 both Angelman and Prader-Willi The chromosomes are inherited in an indentical fashion as other chromosomes so the ratios could be predicted using Mendialian laws. This deletion is not sex linked so there would be not differences between the sexes.

How many Barr bodies would you expect to find in a cell from a person with the following genotype? 1. XXY 2. XY 3. XX 4. XYY 5. XXX 6. XO (only one X)

1. 1 2. 0 3. 1 4. 0 5. 2 6. 0

In the following examples, plants with either green, white, or variegated leaves are crossed. Match the cross with the expected phenotypes of the progeny. Labels may be used more than once. 1. Variegated female crossed with green male 2. Green female crossed with variegated male 3. White female crossed with green male 4. Variegated female crossed with white male

1. white, green, or variegated 2. All green 3. All white 4. white, green, or variegated

A male with AS marries a woman with PWS. If this couple were to have children, what is the probability that they would have a child with PWS? Helpful hint: Embryos that inherit two copies of chromosome 15 containing deletions die in utero and are never noticed as a pregnancy.

1/3 All embryos containing two copies of chromosome 15 with deletions will die, leaving three possibilities. In one scenario, the child will receive a chromosome 15 with a deletion, and a chromosome 15 with a silenced AS gene. This child will have Angelman syndrome. A second possibility is a child who has a chromosome 15 with a deletion, and a chromosome 15 with a silenced PWS gene. This child will have Prader-Willi syndrome. The final child will receive one active copy of each gene (the other copy of each will be silenced) and will be phenotypically normal.

A male with AS marries a woman with PWS. If this couple were to have children, what is the probability that they would have a normal child (does not have PWS or AS)? Helpful hint: Embryos that inherit two copies of chromosome 15 containing deletions die in utero and are never noticed as a pregnancy.

1/3 All embryos containing two copies of chromosome 15 with deletions will die, leaving three possibilities. In one scenario, the child will receive a chromosome 15 with a deletion, and a chromosome 15 with a silenced AS gene. This child will have Angelman syndrome. A second possibility is a child who has a chromosome 15 with a deletion, and a chromosome 15 with a silenced PWS gene. This child will have Prader-Willi syndrome. The final child will receive one active copy of each gene (the other copy of each will be silenced) and will be phenotypically normal.

If the F2 generation is allowed to interbreed to produce an F3 generation, what percentage of sinistral heterozygotes in the F3 had a mother with the dd genotype?

100% Snail coiling morphology is controlled by a maternal effect gene. Because sinistral (d) is recessive to dextral (D), all sinistral progeny come from a dd mother.

A sinistral male (dd) and dextral female (DD) are mated and produce all dextral progeny in the F1 generation. If the F1 progeny are allowed to mate with one another, what percentage of the F2 snails will have a dextral coiling pattern?

100% Snail coiling morphology is controlled by a maternal effect gene. The F1 progeny will all be Dd. Because the F1 females are Dd, the F2 progeny will all be dextral.

You have available a dwarf male mouse with the genotype Igf2m Igf2m and a dwarf female with the genotype Igf2m Igf2. What is the minimum number of generations it would take to produce a normal male? Hint: mice inbreed happily.

2 When you mate the dwarf male mice to the dwarf female mice, the offspring will be half Igf2m Igf2m and half Igf2m Igf2. However, because the mice received their functional copy of Igf2 from their mother, it will be transcriptionally silent, and all animals will be dwarf. If you take an Igf2m Igf2 male and cross it with any of its female siblings, half of the offspring will receive a functional Igf2 gene from their father, and will be normally sized.

A black male and an orange female produce a litter of both male and female kittens that are allowed to mate with one another. What percentage of the female F2 will be orange?

50%

A maternal effect gene has two alleles, dextral (D) is dominant to sinistral (d). Given the following crosses, what phenotypic ratios would you expect for the progeny?

All sinistral: dd female & DD male; dd female Dd male All dextral: DD female & dd male; Dd female & Dd male; Dd female & dd male

Who originally identified a highly condensed structure in the interphase of nuclei?

Barr

Which of the following is not a possible outcome from a mating between a calico female and an orange male?

Black female

A sinistral female is mated with a sinistral male and only dextral progeny are produced. What is the genotype of the female from this cross?

Dd

In which type of inheritance does a change in phenotype of the offspring not rely on a change in the DNA sequence?

Epigenetic inheritance

A researcher incorrectly hypothesized that the alleles controlling leaf coloration are co-dominant and obey Mendel's law of segregation. She proposed that the LG allele produces green pigment and that the LW allele produces no pigment (white coloration). By this reasoning the variegated phenotype is found in LGLW individuals. What outcome would this hypothesis predict from a mating between a variegated female and a white male?

Exactly 1/2 of the progeny show the variegated phenotype.

Which of the following is false regarding human mtDNA?

False: It is a linear chromosome. True: It is around 17,000 bp in length. Multiple copies exist in each mitochondria. It mostly contains rRNA and tRNA genes, and genes for mitochondrial function.

Monoallelic expression is associated with which of the following?

Genomic imprinting

In four o'clock plants, where are the genes that determine leaf coloration located?

In the chloroplast genome of the egg.

What is the geneotype of the father for a snail that has the genotype Dd and has a left hand twist shell?

It cannot be determined. In maternal effect the gneotype and phenotype of the male has no impact on the phenotype of the offspring.

If a snail that has a right hand twist and is DD is mated to a snail that has a left hand twist and is dd what is the expected ratio of progeny?

It depends on which snail is female and which is male.

What type of inheritance is observed with extranuclear DNA?

Maternal inheritance

Which nucleotide modification occurs in imprinting a gene?

Methylation

Which of the following is a mechanism to imprint genes?

Methylation of cytosine

The endosymbiosis theory states that chloroplasts and mitochondria were evolved from bacteria. Which of the following statements supports this theory (statements may or may not be true)?

Mitochondria and chloroplasts have circular genomes.

In snail shell coiling, which of the following is responsible for the phenotype of the offspring?

Mother's genotype

What is thought to be the origin of mitochondria and chloroplasts?

Purple bacteria for mitochondria, cyanobacteria for chloroplasts

PWS lacking genes

SNRNP NDN snoRNA

Who is largely responsible for proposing the endosymbiosis theory?

Schimper, Wallin, Margulis

A calico female and black male produced a litter of two calico females and 1 calico male. What is the best explanation for the calico male?

The calico male received a Y chromosome from the father and two X's from the mother.

What is the phenotype of the father of a woman who has Prader-Willi syndrome?

The father could have two normal copies of chromosome 15 and therefore wouldn't have either syndrome. Since Prader Willi syndrome results from the imprinted region being inherited from the mother the father has to donate a normal chromosome 15 and therefore is most likely to be non-syndromic since these PWS and AS are rare.

In a mating between a variegated female and a white male, the researcher from the previous question found green, white and variegated leaf plants. The presence of which phenotypic class(es) disproves the co-dominance hypothesis from the previous question?

The green leaf plants.

What is extranuclear inheritance?

The inheritance of genetic material that is not found within the nucleus.

If an individual is afflicted with Angelman syndrome (AS), which of the following is true?

The maternal chromosome 15 carries a deletion.

Two phenotypically normal mice produce a single F1 male progeny that is also phenotypically normal. This F1 male is mated with an Igf2 Igf2 female and ½ of the progeny are dwarf. Where did the Igf2m allele in the F2 progeny originate?

The parental generation female that had to have been heterozygous (Igf2 Igf2m). Because the F1 male was phenotypically normal, we can conclude he received a normal copy of the Igf2 allele from his father (the maternal copy of the Igf2 gene is silenced). Therefore, he must have received the Igf2m from his mother.

If an individual is afflicted with Prader-Willi syndrome (PWS), which of the following is true?

The paternal chromosome 15 carries a deletion.

A black female cat (XBXB) and an orange male cat (XOY) were mated to each other and produced a rare male calico cat. What occurred during gamete production to produce this cat?

The sex chromosomes didn't separate during meiosis in the male parent. The male cat inherited two sex chromosomes from his father so this indicates the non-disjunction event occurred in the male parent.

Which of the following are true with regard to mitochondria? Check all that apply.

They can have more than one copy of their chromosome. Mutations to the mitochondrial chromosome can cause diseases in humans. They synthesize some of their own proteins inside the organelle. Mitochondrial genes are similar to bacterial genes.

AS lacking gene

UBE3A

A black female cat (XBXB) and an orange male cat (XOY) were mated to each other and produced a rare male calico cat. Which sex chromosomes did the male inherit from its mother? (Remember the presence of the Y chromosome determines maleness in mammals.) Recall that the mother was XBXB and the father was XOY.

XB If the male is calico, he must inherit an XB allele from his mother.

A black female cat (XBXB) and an orange male cat (XOY) were mated to each other and produced a rare male calico cat. What is the most likely genotype of the male calico cat?

XBXOY The cat is male, so he had to inherit a Y chromosome. However, he is calico, so he must have also inherited an XO allele.

A black female cat (XBXB) and an orange male cat (XOY) were mated to each other and produced a rare male calico cat. Which sex chromosomes did the male inherit from its father? (Remember the presence of the Y chromosome determines maleness in mammals.) Recall that the mother was XBXB and the father was XOY.

XOY The cat is male so he had to inherit a Y chromosome from his father. However, we know that this cat is a rare calico male. That means that he has an XB from his mother, and XOY from his father.

A modification that occurs to a nuclear gene that alters gene expression without modifying the DNA sequence is called __________ inheritance.

epigenetic

The inheritance patterns of genetic material that is not contained in the nucleus of the cell is called __________.

extracellular inheritance

The inheritance of leaf pigmentation in the four-o'clock plant Mirabilis jalapa is an example of __________.

maternal inheritance

Maternal effect patterns of inheritance refer to genes whose expression is controlled by __________.

maternal nuclear genes

mtDNA stands for __________ and cpDNA stands for __________.

mitochondrial DNA; chloroplast DNA

If the sperm cell contributes mitochondria to the oocyte, it is called __________.

paternal leakage

Dosage compensation offsets the problems associated with differences in the number of __________ chromosomes in many species.

sex

A dwarf female mouse is heterozygous for the Igf2 gene (Igf2 Igf2m). You can conclude that __________.

the Igf2m allele came from the father

A trait controlled by a maternal effect gene is dictated by __________.

the genotype of the mother's somatic cells