Chapter 13 Flashcards
Mendelian genes have specific loci (positions) on chromosomes. Chromosomes undergo segregation and independent assortment
Chromosome Theory of Inheritance
Mammals have two types of sex chromosomes: a lager X chromosome and a smaller Y chromosome.
A gene that is located on either sex chromosome is called this. Genes on Y chromosome-Y linked genes. Genes on X chromosome X-linked genes.
Sex-Linked Genes
What sex linked gene help determines sex?
Y chromosome (Y-linked genes)
What chromosomes have genes for many characteristics unrelated to sex?
X chromosomes
What are examples of X linked diseases?
Colorblindness, Hemophilia, Duchenne muscular dystrophy
What sex linked gene is most common and has more genes?
X- sex linked gene (X chromosomes)
We all have XX chromosomes as women but randomly in some cells, an x can be inactivated. One of the two x chromosomes in each cell is randomly inactivated during embryonic development. The inactive x condenses into what?
X Inactive in Female Mammals
The inactive x condenses into a…Barr Body
Located on the same chromosome that tends to be inherited together
Genes
Large-scale chromosomal alterations in humans and other mammals often lead to spontaneous abortions (miscarriages) or cause a variety of developmental disorders.
Alterations Chromosome Number
What tolerates the alterations of chromosome number genetic changes better than animals do?
Plants
Pairs of homologous chromosomes do not separate normally during meiosis. As a result, one gamete receives two of the same type of chromosome, and another gamete receives no copy.
Nondisjunction
Not a normal number of chromosomes. Cause is where chromosomes don’t pull apart appropriately. Results from fertilization involving gametes in which nondisjunction occurred.
Aneuploidy
Alterations of Chromosome Structure include:
-Deletion
-Duplication
-Inversion
Removes a chromosomal segment
Deletion
Repeats a segment
Duplication
