Chapter 6: Problem 8
Describe the origin of cultivated American cotton.
Chapter 6: Problem 8
Describe the origin of cultivated American cotton.
All the tools & learning materials you need for study success - in one app.
Get started for freeHuman adult hemoglobin is a tetramer containing two alpha (a) and two beta ( \(\beta\) ) polypeptide chains. The \(\alpha\) gene cluster on chromosome 16 and the \(\beta\) gene cluster on chromosome 11 share amino acid similarities such that 61 of the amino acids of the \(\alpha\) -globin polypeptide ( 141 amino acids long) are shared in identical sequence with the \(\beta\) -globin polypeptide \((146\) amino acids long. How might one explain the existence of two polypeptides with partially shared function and structure on two different chromosomes? Include in your answer a link to Ohno's hypothesis regarding the origin of new genes during evolution.
In a recent cytogenetic study on 1021 cases of Down syndrome, 46 were the result of translocations, the most frequent of which was symbolized as $t(14 ; 21) .$ What does this designation represent, and how many chromosomes would you expect to be present in \(t(14 ; 21)\) Down syndrome individuals?
In a human genetic study, a family with five phenotypically normal children was investigated. Two children were "homozy. gous" for a Robertsonian translocation between chromosomes 19 and 20 (they contained two identical copies of the fused chromosome). They have only 44 chromosomes but a complete genetic complement. Three of the children were "heterozygous" for the translocation and contained 45 chromosomes, with one translocated chromosome plus a normal copy of both chromosomes 19 and \(20 .\) Two other pregnancies resulted in stillbirths. It was later discovered that the parents were first cousins. Based on this information, determine the chromosome compositions of the parents. What led to the stillbirths? Why was the discovery that the parents were first cousins a key piece of information in understanding the genetics of this family?
A 3 -year-old child exhibited some early indication of Turner syndrome, which results from a \(45, \mathrm{X}\) chromosome composition. Karyotypic analysis demonstrated two cell types: \(46, \mathrm{XX}\) (normal) and \(45, \mathrm{X}\). Propose a mechanism for the origin of this mosaicism.
Review the Chapter Concepts list on page \(99 .\) These all center on chromosome aberrations that create variations from the "normal" diploid genome. Write a short essay that discusses five altered phenotypes that result from specific chromosomal aberrations.
What do you think about this solution?
We value your feedback to improve our textbook solutions.