Ch 5 Quiz + Homework

What is penetrance?

In chickens, the dominant allele Cr produces the creeper phenotype (having extremely short legs). However, the creeper allele is lethal in the homozygous condition. The homozygous recessive genotype results in a normal individual. If two creepers are mated, what will be the phenotypic ratio among the living offspring? 3 normal : 1 creeper 3 creepers : 1 normal 2 normal : 1 creeper 2 creepers : 1 normal 1 normal : 1 creeper

A gene has three alleles. How many different genotypes are possible at this locus in a diploid organism? 5 3 7 4 6

What type of gene action occurs when one gene masks the effect of another gene at a different locus? genomic imprinting anticipation epigenetics complementation epistasis

In humans, mitochondrial genetic disorders are inherited from only the mother. The severity of such diseases can vary greatly, even within a single family. What form of inheritance does this represent? genomic imprinting cytoplasmic inheritance sex?limited inheritance sex?influenced inheritance genetic maternal effect

A recessive mutant allele of an autosome gene in a species of mouse results in a shorted tail in males when homozygous. However, when homozygous in females, this genotype has no effect, and the mice have normal tails. What is this genetic phenomenon called? cytoplasmic inheritance genetic maternal effect sex?influenced characteristic genomic imprinting sex?limited characteristic

A gene whose expression is affected by the sex of the transmitting parent demonstrates which of the events? genetic maternal effect epigenetics pleiotropy genomic imprinting anticipation

With genetic maternal effect, the phenotype of an individual is determined by which of the statements? cytoplasmic genes usually located in the mitochondria the sex of the parent who transmits the gene to the individual a combination of environmental factors and the genotype of the individual the nuclear genotype of the maternal parent the sex of the individual with only one sex able to express the genotype

What is the phenomenon called where there is stronger or earlier expression of a genetic trait in succeeding generations? epistasis pleiotrophy variable expressivity anticipation reduced penetrance

Suppose a species of tulip has three alleles for the gene that codes for flower color. The allele produces red tulips, the allele produces purple tulips, and the allele produces white tulips. is dominant over and , and is dominant over . For each cross, determine the expected phenotype ratio of offspring flower color.

Use the interactive Punnett Squares, Level 5 to answer the questions. How many phenotypes result from a cross between the two parents in the interactive? number of phenotypes: What percentage of the offspring are predicted to have the AB blood phenotype? percentage of offspring with AB blood: % For an individual with O type blood, what would the blood cell look like in the interactive? both triangle and circle?shaped antigens triangle?shaped antigens a different shape of antigens no antigens circle?shaped antigens

Which statement below defines epistasis? when a single gene affects several phenotypes proportion of individuals with an abnormal genotype that exhibit its associated phenotype when one gene influences or masks the effect of another gene when a heterozygote displays a phenotype intermediate between its two alleles

Suppose two independently assorting genes are involved in the pathway that determines fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store. At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for a colored squash. At the second locus, the allele Y codes for a dominant yellow phenotype, and the allele y codes for a recessive green phenotype. The phenotypes from the first locus will always mask the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis. A dihybrid squash, Ww Yy, is selfed and produces 320 offspring. How many offspring are expected to have the white, yellow, and green phenotypes? number of white offspring: number of yellow offspring: number of green offspring:

An allelic series determines coat color in rabbits: C (full color), cch (chinchilla, gray color), ch (Himalayan, white with black extremities), and c (albino, all white). The C allele is dominant over all others, cch is dominant over ch and c, ch is dominant over c, and c is recessive to all other alleles. This dominance hierarchy can be summarized as C > cch > ch > c. The rabbits in the table are crossed and produce the progeny shown. Cross Parents Offspring A full color × albino 50% full color, 50% albino B Himalayan × albino 50% Himalayan, 50% albino C full color × albino 50% full color, 50% chinchilla D full color × Himalayan 50% full color, 25% Himalayan, 25% albino E full color × full color 75% full color, 25% albino Match the parental genotypes to the letter corresponding to the appropriate cross listed in the table.

How are mitochondrial genes typically inherited? An individual randomly inherits their mitochondrial DNA from either parent. An individual inherits their mitochondrial DNA from their father. An individual inherits their mitochondrial DNA from their mother. An individual inherits one copy of mitochondrial DNA from each parent.

Alpers' disease is a mitochondrially inherited disease with symptoms that include seizures, dementia, blindness, liver dysfunction, and cerebral degeneration. The pedigree shows the presence of Alpers' disease in three generations. Individual 4 had one daughter and two sons, and individual 6 had two daughters and one son. Which of the individuals indicated are affected by Alpers' disease? Place the correct symbols on the pedigree showing affected and unaffected individuals. Generation 1 consists of white square 1 and black circle 2, which mate and produce individual 4, individual 5, and black square 6. A second generation white square 3 mates with individual 4 to produce black circle 8, black square 9, and individual 10 in the third generation. Black square 6 mates with a second generation individual 7 to produce white circle 11, white circle 12, and white square 13 in the third generation. black square white circle black circle black square

Penile hypospadias, a birth defect in male humans in which the urethra opens on the shaft instead of at the tip of the penis, results from an autosomal dominant gene in some families. Females who carry the gene show no effects. What type of trait is this birth defect an example of? a sex?limited trait because the defect occurs only in males and the gene involved is autosomal a genetic maternal effect because the presence of the trait depends upon the genotype of the mother a sex?influenced trait because the defect occurs only in males and the gene involved is autosomal a Y?linked trait because the defect occurs only in males an X?linked trait because the defect occurs more often in males than in females

Male?limited precocious puberty results from a rare, sex?limited autosomal allele (P) that is dominant over the allele for normal puberty (p) and is expressed only in males. Bill undergoes precocious puberty, but his brother Jack and his sister Beth underwent puberty at the usual time, between the ages of 10 and 14. Although Bill's mother and father underwent normal puberty, his two maternal uncles (his mother's brothers) underwent precocious puberty. All of Bill's grandparents underwent normal puberty. Match the most likely genotypes for each relative in his family. If there is an equal likelihood of multiple genotypes for a relative, place each possible genotype. Relative Genotype Bill Bill's brother Jack Bill's sister Beth Bill's father Bill's mother Bill's uncle Bill's grandfather Bill's grandmother Answer Bank Pp pp PP