BIOL 3333 1st Edition Lecture 16 Current LectureTelomreres:- specialized structures found at the very endof linear chromosomes Chromosome Parts:Where does chromosome pairing occur?- between between pseudoautosomal regions of X and Y where they share DNA homology What does Heterochromatin do?- it stains darkly, replicates later in S phase - contains few genesWhich heterochromatin is always genetically inactive?- the Y heterocrhomatin - the constitutive heterochromatin Do males and females differ in the number of genes present on X chromosome?- YESHow many more X’s do females have than males?- twice the number of X’s - two vs one x chromosomeWhat did Bertram and Barr do in 1948?These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- the Examination of interphase nuclei in males and femalesWhat did Mary Lyon do in the early 1960’s? - experiments with sex-linked coat color genes in mice What is the Lyon Hypothesis?- Facultative heterochromatin is formed as a result of a developmental event - inactivation of an X chromosome What happens to the female in embryogenesis?- one of the 2 X chromosomes is randomly inactivatedWhat is the consequence of early and random inactivation?- it leads to mosaicism in all body tissues *The X and Y chromosomes of humans do not share extensive DNA similarity*There is a dosage compensation mechanisms that corrects for differences between males and females in the number of X chromosomes What is Anhydrotic Dysplasia?- a defect in sweat gland distribution in the epidermis -GRANDMOTHER-MOTHER -IDENTICAL TWINS *The X and Y chromosomes of humans of not share extensive DNA similarity*There is a dosage compensation mechanism that corrects for differences between males and females in the number of X
View Full Document
Unlocking...