first section basic genetics laboratory.pptx

There are two x chromosomes in female cells and one x and one y chromosome at male cells .as y is a chromosome with afew genes ,there will be some dosage problems and differences among both sexes.In order to dose compensate the female cell silence one of its x chromosomes called x-inactivation process and the x chromosome will be called Barr Body .
In these slides I try to examine the cells to show students the cell ability to silence a x chromosome

1. Basic Genetics Laboratory first section Dr.Afagh Bapirzadeh

2. Why do we study genetics? Genetics is necessary To understand one's body it Has connectivity with other medical sciences Genetics is the study of genes, mutations, and hereditary in living organisms.

3. Genomes ,genes ,DNA The whole genetic material of one person is called the genome The nucleus in a eukaryotic cell consists of chromosomes Human has 23 pairs of chromosomes

4. Chromosomes And Their Structures Each chromosome has one long arm called the q-arm Each chromosome has one short arm called the p arm At the end of the chromosomes there are telomeres The chromosome has a centromere

5. Categorizing chromosomes based on the centromere There are 4 types of chromosomes based on the place of the centromere Metacentric, sub-metacentric, acrocentric, telomeric In acrocentric we have satellites In telocentric we don’t have p-arm

6. Human sex chromosomes In women the sex chromosomes are XX In men the sex chromosomes are XY Chromosome X is much bigger than chromosome Y and has more genes in it But does it make sense that women should have more genes than men?

7. Dosage compensation Female has 2 X chromosomes which are inherited from both of her parents (each from one of them) Men have one small Y chromosomes which barely have some genes To compensate for this injustice one of the X chromosomes in female cells is silenced

8. What is a barr body In all of the female cell one of the X chromosomes is silenced It is called Barr Body It usually attaches to the cell corner Doesn’t participate in transcription and translation

9. How does dosage compensation happen As it is shown in the picture, the X-inactivation process is random It may affect paternal X or maternal X After cell division, each descendant of the inactive X will be silenced in the cells This process starts on day 3 of zygote to in a week

10. The laboratory procedure Wash your mouth Choose a swape and touch the inner part of your cheeks Push the swap against a clean slide Stain the slide and watch the barr bodies