Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
THE CHROMOSOME THEORY OF INHERITANCE AND SEX CHROMOSOMES
|
describes how the transmission of chromosomes account for the Mendelian patterns of inheritance
-This theory was independently proposed in 1902-03 by Theodore Boveri and Walter Sutton |
|
|
The chromosome theory of inheritance is based on a few fundamental principles
|
1. Chromosomes contain the genetic material
2. Chromosomes are replicated and passed along from parent to offspring 3. The nuclei of most eukaryotic cells contain chromosomes that are found in homologous pairs During meiosis, each homologue segregates into one of the two daughter nuclei 4. During the formation of gametes, different types of (nonhomologous) chromosomes segregate independently 5. Each parent contributes one set of chromosomes to its offspring The sets are functionally equivalent Each carries a full complement of genes |
|
|
Mendel’s law of segregation can be explained by the
|
homologous pairing and segregation of chromosomes during meiosis
|
|
|
Mendel’s law of independent assortment can be explained by the
|
relative behavior of different (nonhomologous chromosomes) during meiosis
|
|
|
. ZW system
|
which is found in birds, butterflies, moths and some fishes
Females are heterogametic (ZW) Males are homogametic (ZZ) |
|
|
XO system,
|
which is found in many species of insects
Females have two X chromosomes (XX) Males have only one (XO) |
|
|
X chromosome-autosome balance system,
|
which is found in Drosophila
The main factor in sex determination is the ratio between the number of X chromosomes and that of the number of sets of autosomes The Y chromosome is essential for male fertility NOT male development |
