30 Questions
What is the genotype of a male who expresses a sex-linked recessive trait?
Hemizygous Xa
What is the probability that a son inherits an X-linked recessive allele from a carrier mother?
50%
What is the notation for an X-linked dominant allele?
XA
A female who is homozygous for an X-linked dominant allele will transmit the allele to which of her offspring?
All sons and daughters
What is the term used to describe males who have only one X chromosome in relation to sex-linked genes?
Hemizygous
A male who is affected by an X-linked recessive trait will transmit the allele to which of his offspring?
Only daughters
What is the probability that a child will have the trait if a carrier mates with a male who has the trait?
50%
What is the name of the gene on the human X chromosome that causes Duchenne muscular dystrophy?
DMD
What is the name of the coagulation factor IX gene on the human X chromosome that causes Haemophilia B?
F9
What is the notation for the genotype of a carrier female who has one copy of the X-linked recessive allele?
XA Xa
What is the proportion of males affected by Haemophilia A?
1/10,000
Why do many more males than females have sex-linked disorders?
Because males have XY chromosomes
What is the expected phenotypic ratio if the genes controlling body colour and wing size are genetically unlinked?
1:1:1:1
Why are the recombinant phenotypes underrepresented in Morgan's experiment?
Because the genes are closely physically linked
What is the primary difference between Morgan's experiment and Mendel's dihybrid crosses in pea plants?
Genetic linkage of the genes
What is the purpose of studying genetic linkage in Drosophila melanogaster?
To understand genetic inheritance patterns
What increases the likelihood of recombination between linked genes?
Physical distance between the genes
What can be inferred about the genes controlling body colour and wing size in Drosophila melanogaster?
They are located close together on the same chromosome
What is the primary purpose of the fluorescent yellow dye in the image?
To tag a specific gene on the chromosomes
What was the significant discovery made by Thomas Hunt Morgan in the 1900s?
The association of a specific gene with a specific chromosome
What is the main concept that explains how genes are inherited?
The chromosomal basis of Mendel's laws
What is the term for a segment of DNA that carries information necessary for the development of an organism?
Gene
What is the term for a variation of a gene that results in a different phenotype?
Allele
What is the organism that was used by Thomas Hunt Morgan to study the chromosomal basis of inheritance?
Drosophila melanogaster
What is the genotype of the wild type Drosophila melanogaster female in the experiment?
b+ b+ vg+ vg+
What is the phenotype of the offspring if the genes for body colour and wing size are not linked?
All offspring will have a combination of grey bodies and vestigial wings or black bodies and normal wings.
What is the purpose of crossing the wild type female with a male that has both mutant phenotypes in the experiment?
To determine the genetic linkage between the body colour and wing size genes.
What is the notation for the mutant allele of the body colour gene?
b
Why are the genes for body colour and wing size not sex-linked in Drosophila melanogaster?
Because they are on an autosomal chromosome.
What is the result of the experiment performed by Thomas Hunt Morgan and his team?
The genes for body colour and wing size are linked.
Understand how sex-linked traits are transmitted from parents to offspring in mammals, including the role of X chromosomes and recessive alleles. Learn how males and females transmit X-linked alleles and how they express sex-linked traits. Test your knowledge of sex-linked inheritance!
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
