Exam 23: Patterns of Gene Inheritance

Huntington disease is an autosomal dominant disorder that leads to progressive degeneration of brain cells.There is no effective treatment for the disorder and individuals usually die 10 to 15 years after the onset of symptoms.Which of these statements about Huntington disease is true?

If an organism shows a recessive phenotype,such as short pea plants,its genotype can be

How many alleles are required to express a monohybrid trait?

A cross that involves two traits is called a ______ cross.

If the genotype of an organism is YySsTt,then yST would represent

In which kind of cross would you expect to find a phenotypic ratio of 3:1 among the F₂ offspring?

Which genetic disorder is associated with an irregular shape of the red blood cells?

A pheasant breeder starts with two birds in the P generation,one of which is AA and the other is aa.If he takes two of the birds from the F₁ generation and breeds them together,what can he expect in his F₂ offspring?

In humans,brown eyes (B)is a simple dominant trait over blue eyes (b).A brown-eyed woman whose child is blue-eyed would have the genotype

For Mendel's law of segregation to occur,the alleles must be

All but one of the following experiments would allow a scientist to discover if the phenotype of an organism would be affected by environmental changes; choose the experiment that would not show environmental effects.

Which of the following is NOT correct concerning the law of independent assortment?

Alternative forms of a gene that influence the same trait and are found at the same location in homologous chromosomes are called

In a Mendelian monohybrid cross involving two homozygous genotypes,the ____ generation is always completely heterozygous.

In the human population short fingers are dominant over long fingers.Indicate the genotypic and phenotypic ratios if a heterozygous short fingered female reproduces with a long fingered male.

Which of the following represents the physical characteristics of the individual?

What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?

Some plants fail to produce chlorophyll,and this trait appears to be recessive.Many plants also self-pollinate.If we locate a pea plant that is heterozygous for this trait,self-pollinate it and harvest seeds,what are the likely phenotypes of these seeds when they germinate?

What are the chances that two individuals with wavy hair (an incomplete trait)will have a curly-haired child? Curly hair and straight hair exhibit incomplete dominance.

A blue-eyed,left-handed woman marries a brown-eyed,right-handed man who is heterozygous for both of his traits.If blue eyes and left-handedness are recessive,how many different phenotypes are possible in their children?