Coconote
AI notes
AI voice & video notes
Export note
Try for free
Meiosis and Its Role in Genetic Diversity
Oct 6, 2024
π€
Take quiz
πΊοΈ
Mindmap
Understanding Meiosis and Genetic Diversity
Key Concepts
Meiosis
is the process that generates gametes for reproduction.
It produces
haploid cells
from a
diploid cell
.
Important for genetic diversity in offspring.
Meiosis Process Overview
Location
: Occurs in germ cells within the gonads of males and females.
Divisions
: Two rounds -
Meiosis I
and
Meiosis II
.
End Result
: Meiosis results in four haploid cells (gametes).
Differences Between Mitosis and Meiosis
Mitosis
: Produces 2 diploid daughter cells.
Meiosis
: Produces 4 haploid daughter cells.
Both begin after G1, S, and G2 stages of interphase.
Stages of Meiosis
Meiosis I
Prophase I
:
Homologous pairs of sister chromatids lie side by side (synapsis).
Formation of
tetrad (bivalent)
.
Crossing over
occurs, increasing genetic diversity.
Metaphase I
:
Tetrads align randomly along metaphase plate (independent assortment).
Anaphase I
:
Homologous chromosomes separate.
Telophase I
:
Chromosomes de-condense, nuclear envelope reforms.
Cytokinesis separates two daughter cells.
Meiosis II
Prophase II
:
Sister chromatids condense; spindle forms.
Metaphase II
:
Sister chromatids aligned along the metaphase plate.
Anaphase II
:
Sister chromatids separate and move to poles.
Telophase II
:
Chromosomes de-condense, nuclear envelope reforms.
Cytokinesis separates the cells into four haploid daughter cells.
Genetic Diversity Mechanisms
Crossing Over
: Exchange of DNA between non-sister chromatids during prophase I.
Independent Assortment
: Random alignment of homologous chromosomes during metaphase I.
Results in increased genetic combinations:
Formula: 2^n (where n = number of chromosome pairs).
In humans (n = 23): 2^23 = over 1 million combinations.
Conclusion
The combination of crossing over and independent assortment leads to genetic diversity.
Explains why children do not look exactly like their parents and why siblings may look different.
π
Full transcript