Exam 13: Mendel and the Gene

What is the probability that a gamete from an individual with the genotype E₁E₂X₁X₁A₁A₂M₂M₂ will contain all paternally derived homologues?

In humans,blue eyes are inherited as a recessive autosomal trait and color blindness is an X-linked recessive trait.A woman with blue eyes and normal color vision whose father was color blind marries a man who also has normal color vision.He has brown eyes but his mother had blue eyes.Which of the following do you expect to be true for their daughters?

Whenever the dominant allele of either (or both)gene A or gene B is present,red color is produced.A cross of AaBb × AaBb can be expected to yield how many red offspring out of 16? Assume the genes are not linked.

In Drosophila melanogaster,vestigial wings are caused by a recessive allele of a gene that is linked to a gene with a recessive allele that causes black body color.Morgan crossed black-bodied,normal-winged females and gray-bodied,vestigial-winged males.The F₁ were all gray bodied,normal winged.After examining the F₂ progeny,Morgan calculated the map distance to be 17 map units.Which of the following is correct about the F₂ progeny?

Hemophilia is caused by several genetic factors;one,a recessive allele of an X-linked gene,is the subject of this problem.Assume that a man with hemophilia marries a normal woman whose father had hemophilia.What is the probability that their first son will have hemophilia?

In rabbits,the homozygous CC is normal,Cc results in deformed legs,and cc results in very short legs.The genotype BB produces black fur,Bb brown fur,and bb white fur.If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs,what percentage of the offspring would be expected to have deformed legs and white fur?

Snapdragons are flowers that come in a variety of colors,including red,pink,and white.A series of crosses with snapdragons having flowers of different colors produced the following results: pink × pink: 27 pink,13 red,14 white Red × red: all red White × white: all white Pink × white: 29 pink,26 white Pink × red: 28 pink,27 red White × red: all pink Based on the results,what is the most reasonable explanation for the inheritance of these flower colors?

A man is heterozygous for two genes (R and L)that are located on different chromosomes.Which of the following processes would result in different combinations of the alleles for these two genes in his sperm?

The B-globin gene has many alleles.What is the maximum number of different alleles of the B-globin gene that could be carried by 6 children with the same mom and dad given that the parents are heterozygous?

A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers.The F₁ all had red fruit and yellow flowers.The following phenotypes were obtained in the F₂: Red fruit and yellow flowers-41 Red fruit and white flowers-7 Golden fruit and yellow flowers-8 Golden fruit and white flowers-44 How many map units separate these genes?

A recessive allele on the X chromosome is responsible for red-green color blindness in humans.A woman with normal vision whose father is color blind marries a color-blind male.What is the probability that this couple's first son will be color blind?

The second child of the couple above is unaffected (does not display the condition).What is the probability this child is a carrier for the ataxia condition?

In birds,sex is determined by a ZW chromosome scheme that is much like the typical XY scheme seen in humans and many other organisms,except that the system is reversed: Males are ZZ (similar to XX in humans)and females are ZW (similar to XY in humans).A lethal recessive allele that causes death of the embryo occurs on the Z chromosome in pigeons.What would be the sex ratio in the offspring of a cross between a male heterozygous for the lethal allele and a normal female?

In humans,ABO blood types refer to glyocproteins in the membranes of red blood cells.There are three alleles for this autosomal gene: IA,IB,and i.The IA allele codes for the A glycoprotein,the IB allele codes for the B glycoprotein,and the i allele doesn't code for any membrane glycoprotein.IA and IB are codominant,and i is recessive to both IA and IB.People with A type blood have the genotypes IAIA or IAi,people with type B blood are IBIB or IBi,people with type AB blood are IAIB,and people with O type blood are ii.If a woman with type AB blood marries a man with type O blood,which of the following blood types could their children possibly have?

Glucose-6-phosphate dehydrogenase deficiency (G6PD)is inherited as a recessive allele of an X-linked gene in humans.A woman whose father suffered from G6PD marries a normal man.(a)What proportion of their sons is expected to be G6PD? (b)If the husband was not normal but was G6PD deficient,would you change your answer in part (a)?

Suppose two AaBbCc individuals are mated.Assuming that the genes are not linked,what fraction of the offspring are expected to be homozygous recessive for the three traits?

In humans,blue eyes are inherited as a recessive autosomal trait and color blindness is an X-linked recessive trait.A woman with blue eyes and normal color vision whose father was color blind marries a man who also has normal color vision.He has brown eyes,but his mother had blue eyes.Which of the following do you expect to be true for their sons?

A man and woman are both of normal pigmentation,but both have one parent who is albino (without melanin pigmentation).Albinism is an autosomal (not sex-linked)recessive trait.What is the probability that their first child will be an albino?

A man has extra digits (six fingers on each hand and six toes on each foot).His wife and their daughter have a normal number of digits.Having extra digits is a dominant trait.The couple's second child has extra digits.What is the probability that their next (third)child will have extra digits?

Gray seed color in peas is dominant to white.Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves,and the following progeny were produced: 302 gray and 98 white.(a)What is the most probable genotype of each parent? (b)Based on your answer in (a)above,what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.)