Genetics Problem Test 1

The dominant eye color in humans, based on the genetic problems presented during the introduction to genetics, is brown. This suggests that brown eye color is more prevalent and has a higher likelihood of being inherited compared to other eye colors.

The correct genotype for a male Cyclops that is heterozygous for both traits is [BbNn]. This means that the Cyclops has one dominant allele for barbs (B) and one recessive allele for smooth (b), and one dominant allele for non-resistance to pesticides (N) and one recessive allele for resistance to pesticides (n).

The correct answer is 9, which represents the number of gametes produced by both male and female aquatic cyclops when mated to form F2 generation offspring. In this dihybrid cross, the male and female cyclops can produce four different types of gametes based on the combination of alleles for antennae and resistance to pesticides. The possible combinations are Bn, Bn, Bn, and Bn. Out of the 16 possible offspring in the F2 generation, 9 will have barbed antennae and non-resistance to pesticides.

Homozygous genotypes are made of the same alleles. In homozygous individuals, both alleles for a particular trait are identical. This means that if the individual has a homozygous dominant genotype, both alleles are dominant, and if the individual has a homozygous recessive genotype, both alleles are recessive. Homozygous genotypes are often used to determine the inheritance pattern of traits in genetics.

In a dihybrid cross, the male and female cyclops both have the genotype BbNn. When they mate to form the F2 generation offspring, they can produce four different combinations of alleles in their gametes: BN, Bn, bN, and bn. Out of the 16 possible combinations of alleles in the offspring, only one will have both smooth antennae (bb) and resistance to pesticides (nn). Therefore, the answer is 1.

Heterozygous genotypes are made up of two different alleles. In genetics, alleles are alternate forms of a gene that occupy the same position on a chromosome. Heterozygous individuals have two different alleles for a particular gene, one inherited from each parent. This is in contrast to homozygous individuals, who have two identical alleles, and can be either dominant or recessive. Therefore, the correct answer is heterozygous.

The correct answer is False because if the female dog is homozygous for the deaf gene and the male dog is heterozygous for the deafness gene, there is a possibility that some of the puppies could inherit the deafness gene. Therefore, it is not true that all of the puppies would have normal hearing.

Dominant gene refers to a gene that is always expressed or visible, regardless of whether it is paired with a recessive gene or not. In a heterozygous individual, where two different alleles are present for a specific gene, the dominant allele will determine the phenotype. On the other hand, in a homozygous individual, where two identical alleles are present, if the dominant allele is present, it will be expressed. Therefore, the correct answer is "Dominant".

Sickle-cell is the correct answer because it is a genetic blood condition characterized by abnormal hemoglobin, causing red blood cells to become rigid and sickle-shaped. This condition can lead to various complications such as anemia, organ damage, and pain episodes. Deafness, Hemophilia, and Thalassemia are not related to this specific genetic blood condition.

The given genotype [Tt] represents a heterozygous individual, meaning it has two different alleles for the trait of plant height. In this case, "T" represents the dominant allele for tall height, while "t" represents the recessive allele for short height. Since the dominant allele is present, the phenotype of the individual will be tall pea plant.

The correct answer is [ss]. This is because the person with the genotype [ss] has two copies of the abnormal hemoglobin gene, resulting in the formation of abnormal hemoglobin and the presence of the sickle-cell trait.

The genotype [tt] indicates that both alleles for the trait of plant height are the same and recessive. In this case, the recessive allele for short plant height (t) is present in both copies of the gene. Since there are no dominant alleles present, the genotype is homozygous for the recessive trait.

The given genotype [Rr] represents a heterozygous condition for the trait of round pea seeds (R) and wrinkled pea seeds (r). Heterozygous means that the individual has two different alleles for the same trait, in this case, one dominant allele (R) and one recessive allele (r). The dominant allele (R) will be expressed in the phenotype, resulting in round pea seeds.

A trihybrid cross is between two individuals that are heterozygous for three different traits. In this type of cross, the parents carry two different alleles for each of the three traits being studied. The cross allows for the examination of the inheritance patterns for all three traits simultaneously, which can provide valuable information about the genetic interactions and ratios of offspring with different combinations of traits.

A recessive gene is one that is only expressed when an individual has two copies of the gene, meaning they are homozygous for that gene. In the case of this question, the correct answer is "Recessive" because it is the only option that fits the description of a gene that is expressed only in the homozygous state.

A phenotypic ratio of 3:1 in the F2 generation indicates that both parents (F1) are heterozygous for a single trait. This is because in a monohybrid cross between two heterozygotes, there is a 1:2:1 genotypic ratio of homozygous dominant:heterozygous:homozygous recessive. When this genotypic ratio is expressed phenotypically, it results in a 3:1 ratio of the dominant phenotype to the recessive phenotype. Therefore, the F1 generation must be heterozygous for the trait in order to produce this phenotypic ratio in the F2 generation.

When a male four-o-clock plant that is pure red (rr) is pollinated with a female plant that is pink (rw), the offspring will inherit one allele from each parent. This means that 50% of the offspring will inherit the red allele (r) from the male parent and the pink allele (w) from the female parent, resulting in pink flowers (rw). Therefore, out of the total 1,000 plants, 500 offspring will be pink.

The given answer [bb] suggests that the genotype of the mother is homozygous recessive for eye color. Since brown eyes (B) are dominant over blue eyes (b), the fact that the couple has two brown-eyed children and one blue-eyed child indicates that both parents must carry the recessive allele for blue eyes. Therefore, the mother must have a genotype of [bb].

The correct answer is [WW] : [Ww]. This is because when a squash plant homozygous for the white fruit color (WW) is crossed with a plant heterozygous for white (Ww), the possible genotypes of the F1 generation offspring are either homozygous dominant (WW) or heterozygous (Ww) for the white fruit color.

In dogs, hereditary deafness is caused by a recessive gene. This means that the deafness trait will only be expressed if the dog inherits two copies of the recessive gene, one from each parent. If a dog inherits only one copy of the recessive gene, it will be a carrier of the deafness trait but will not be deaf itself. The dominant gene, on the other hand, would cause deafness even if the dog only inherits one copy. Therefore, the correct answer is recessive.

The genotype of the father is [Bb]. This is because brown eyes (B) are dominant over blue eyes (b), so if the father has brown eyes, he must have at least one dominant allele (B). Since they have two brown-eyed children and one blue-eyed child, it means that the father passed on the dominant allele (B) to the brown-eyed children and the recessive allele (b) to the blue-eyed child. Therefore, the father must have a heterozygous genotype (Bb).

The correct answer is [WW] X [ww]. This is because the question states that white fruit color (W) is dominant over yellow fruit color (w). When a squash plant homozygous for white (WW) is crossed with a plant homozygous for yellow (ww), the genotype of the P generation would be [WW] X [ww].

Heterozygous is the correct answer because it refers to a genotype that contains two different forms of genes for a single trait. In this case, the genotype [Mn] indicates that the individual has one dominant allele (M) and one recessive allele (n) for the trait. Heterozygosity often results in a dominant phenotype, as the dominant allele masks the effects of the recessive allele.

In pea plants, smooth seeds (S) are dominant to wrinkled seeds (s). When two plants that are heterozygous for the seed shape trait (Ss) are crossed, the possible genotypes of the offspring are SS, Ss, and ss. Out of these, only the SS and Ss genotypes will result in smooth seeds. Since both of these genotypes have the dominant smooth seed trait, the percentage of offspring with smooth seeds would be 75%.

When a pure red male four-o-clock is pollinated with a pink female (rw), the offspring will inherit one allele from each parent. Since the male is pure red (rr) and the female is pink (rw), the possible combinations of alleles in the offspring are rr and rw. Out of these combinations, half of the offspring will have the rr genotype, which corresponds to the red flower color. Therefore, out of the total 1,000 plants in the F1 generation, 500 plants will be red.

The given answer states that the genotypes [qq] and [jj] are homozygous recessive. In genetics, homozygous recessive refers to having two copies of the same recessive allele for a particular trait. In this case, the alleles represented by [qq] and [jj] are both recessive, as indicated by the lowercase letters. Therefore, these genotypes are homozygous recessive.

The F2 generation having a genotypic ratio of 1:2:1 suggests that both parents in the P generation were heterozygous for the eye color gene. This is because when a homozygous dominant parent (BB) is crossed with a homozygous recessive parent (bb), the resulting F1 generation will all be heterozygous (Bb). When the F1 generation is crossed with each other, the genotypic ratio of the F2 generation will be 1 homozygous dominant (BB), 2 heterozygous (Bb), and 1 homozygous recessive (bb).

In this scenario, both the male and female dogs are homozygous for the deafness gene [d]. Since the deafness gene is dominant over the normal hearing gene [D], all the puppies will inherit at least one copy of the deafness gene from their parents. Therefore, 100% of the puppies will be deaf.

In this scenario, the male four-o-clock is heterozygous for red color (Rr) and the female is pink (rw). Since the male only has the red color allele (R), it can only pass on the red color allele to its offspring. The female has the white color allele (w), but since the male cannot pass it on, none of the offspring in the F1 generation will have the white color allele. Therefore, the number of offspring in the F1 generation that will be white is 0.