Exam 4: Extensions and Modifications of Basic Principles

While studying a new human disease you discover that the disease is linked to a mitochondrial gene.You can be reasonably sure that the disease is inherited _____________________.

If a color-blind female has children,what do we know about all of her sons?

In various crosses examining three different Drosophila traits,you find the following ratios: 9:3:4,9:7,and 12:3:1.What kind of epistasis is each?

What is the sexual phenotype of Drosophila that has XXXY sex chromosomes and two sets of autosomes?

A child who is blood type A has a mother who is blood type B.In a paternity suit a man is accused of being the father.He has blood type AB.Is he the father?

How many Barr bodies are present in an individual with Klinefelter syndrome XXYY)?

Yeast mitochondria have a tubular morphology.In a mutagenic screen,two mutants are isolated that have fragmented mitochondria instead of tubular mitochondria.To determine if these two mutations are at the same or different loci,the two mutants are crossed.The progeny all have tubular mitochondria.What do you conclude?

When studying Arabidopsis a researcher isolates a gene mutation that produces a shorter stem-height phenotype.Interestingly,when this gene is present wild-type plantand the seedling is germinated at the lower temperature of 12 $\degree$ C,the same short-stem phenotype is replicated.This phenomenon is known as

Assume that connected earlobes are a recessive trait with 73% penetrance.The parents are heterozygous and homozygous recessive for the attached earlobe gene.What is the probability that their first child will have attached earlobes?

Males and females express the same amount of X-chromosome genes despite the fact that females have more X chromosomes.Animals approach this problem in different ways.Which of the following is an example?

What kind of dominance does the following example demonstrate? Individuals with the genotype HH have healthy levels of cholesterol,those with Hh have higher levels of cholesterol,and those with hh have dangerous levels that often lead to heart attacks during childhood.

The difference between dominance and epistasis is that

Sex-influenced traits are encoded by ________ genes and sex-linked traits are encoded by _______ genes.

A human with an XY chromosome pair appears female.What might explain this person's condition?

Drosophila melanogaster has been used in genetic studies for over 100 years because of its many useful characteristics.Which of the following is NOT one of these characteristics?

Assume that you are looking at a case of lethal alleles.Crossing two green corn plants results in 2/3 green progeny and 1/3 white progeny.If you crossed two white progeny with each other,how many of the progeny would you predict to be white?

Which statement is true of sperm?

In analyzing continuous characteristics,one cannot observe Mendelian ratios.The reason for this is that continuous characteristics ___________.

When Morgan crossed a red-eyed female with a white-eyed male,which results made Morgan think that the locus affecting eye color was on the X chromosome?

In the ABO blood-type phenotype,which gene is the most epistatic?