BIO 110- Pre-Lecture First Check #7 (covers Tutorials #15-16)

If a male affected by a recessive sex-linked trait reproduces with a female who is homozygous wild type for that trait, what is the chance that any of their offspring will have the trait? 50% 75% 100% 0 25%

0

Here is a cartoon of homologous chromosomes. Sister chromatids are represented by _____ and nonsister chromatids are represented by ________. 2 and 3 1 and 2; 3 and 4 1 and 3; 2 and 43 and 4 1 and 2, 3 and 4; 1 and 3, 1 and 4, 2 and 3, 2 and 4

1 and 2, 3 and 4; 1 and 3, 1 and 4, 2 and 3, 2 and 4

If the recombination frequency between P and O is 7.4, and between N and O it is 7.9, what is the likely order of these genes on the chromosome if the distance between N and P is 15.7? None of these choices N-O-P O-P-N Either P-O-N or N-O-P O-N-P

Either P-O-N or N-O-P

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? XNXN and XNY XNXN and XnY XNXn and XNY XnXn and XnY

XNXn and XNY

Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel's law of segregation? The two alleles for each gene separate as homologous chromosomes move apart during anaphase I. The arrangement of each pair of homologous chromosomes on the metaphase plate during metaphase I is random with respect to the arrangements of other pairs. Sister chromatids separate during anaphase II.

The two alleles for each gene separate as homologous chromosomes move apart during anaphase I.

The locations for three genes have been added to this cartoon. For clarity, the locations have only been noted on one chromatid. The lowest frequency of crossovers would occur between genes ____ and ____. b and c a and b a and c

a and b

SRY is best described as _____. a gene region present on the Y chromosome that triggers male development a gene present on the X chromosome that triggers female development an autosomal gene that is required for the expression of genes on the Y chromosome an autosomal gene that is required for the expression of genes on the X chromosome

a gene region present on the Y chromosome that triggers male development

How do the events of meiosis I promote the production of new combinations of alleles? via both independent assortment and crossing over between sister chromatids via independent assortment alone via crossing over between homologous chromosomes only via both crossing over between homologous chromosomes and independent assortment via crossing over between sister chromatids only

via both crossing over between homologous chromosomes and independent assortment

When genes on a particular chromosome do not assort independently in genetic crosses, the genes are _______________. recombinants wild type linked homozygous alleles not linked

linked

Males are more often affected by sex-linked traits than females because _____. males are hemizygous for the X chromosome male hormones such as testosterone often alter the effects of mutations on the X chromosome female hormones such as estrogen often compensate for the effects of mutations on the X chromosome X chromosomes in males generally have more mutations than X chromosomes in females

males are hemizygous for the X chromosome

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? tortoiseshell females; tortoiseshell males black females; orange males tortoiseshell females; black males orange females; black males

tortoiseshell females; black males

You are working for a fly geneticist who sends you to a produce market to find new mutations. You rummage through the dumpsters and capture 100 flies. You note that 100% of the flies have red eyes and 90% have long body bristles (10% have short body bristles). Based on these results, you can conclude that __________________. red eyes are dominant and short body bristles are recessive short body bristles and long body bristles are located on different chromosomes red eyes and short body bristles are located on different chromosomes in this produce market, red eyes and long bristles are wild-type traits red eyes and long body bristles are inherited in a dominant manner

in this produce market, red eyes and long bristles are wild-type traits

What ratio of F1 generation phenotypes would be expected from a test cross of flies differing in two characters (females are heterozygous for both genes, and males are homozygous recessive for both genes) if the two genes assort independently of each other? 8:2:2:1 1:1:1:1 9:3:3:1 3:3:1:1 5:5:1:1

1:1:1:1

Pull out a piece of paper and pencil because this question will take some thought. First, work out the predicted offspring of a mating between a white-eyed female and a red-eyed male Drosophila. Next, work out the predicted offspring of a heterozygous red-eyed female and a white-eyed male. What is the result of both crosses? In the first case, all females will have white eyes and all males red eyes. In the second case, this is reversed. In the first case, all males will have white eyes. In the second case, this will be reversed. In the first case, all females will have red eyes and all males will have white eyes. In the second case, there will be equal numbers of white and red eyes. In both cases, the result is the same. In the first case, there will be equal numbers of white and red eyes. In the second case, only females will have red eyes.

In the first case, all females will have red eyes and all males will have white eyes. In the second case, there will be equal numbers of white and red eyes.

Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel's law of independent assortment? Sister chromatids separate during anaphase II. The two alleles for each gene separate as homologous chromosomes move apart during anaphase I. The arrangement of each pair of homologous chromosomes on the metaphase plate during metaphase I is random with respect to the arrangements of other pairs.

The arrangement of each pair of homologous chromosomes on the metaphase plate during metaphase I is random with respect to the arrangements of other pairs.

Of the following statements, which is/are usually true if the genes for two different characters are linked? The alleles for each character won't segregate. The genes are on the same chromosome and do not assort independently. The alleles for the linked genes assort independently from one another. A proportional number of parental phenotypes and recombinant phenotypes are represented among offspring. All of the above

The genes are on the same chromosome and do not assort independently.

You are studying two genes that are located on the same chromosome. They are located 55 map units apart. How will the alleles of these genes behave in a dihybrid cross? They will appear to segregate independently, as if they are located on different chromosomes. Can't say without knowing the recombination frequency. They will stay together.

They will appear to segregate independently, as if they are located on different chromosomes.