 Occurs
when homologous pairs line up in a
random order during Metaphase 1 of meiosis
 Occurs
when homologous pairs line up in a
random order during Metaphase 1 of meiosis
 For humans, there are more than 8 million
possible combinations of chromosomes in the
gametes that are produced.
 Occurs
when homologous pairs line up in a
random order during Metaphase 1 of meiosis
 For humans, there are more than 8 million
possible combinations of chromosomes in the
gametes that are produced.
 Identical twins are the only people who have
the same genetic material – there is an
almost impossible chance otherwise.
 Crossing
meiosis.
over occurs during Prophase 1 of
 Crossing
over occurs during Prophase 1 of
meiosis.
 Parts of the chromosome of non-sister
chromatids can cross over at a point called
the chiasma.
 Crossing
over occurs during Prophase 1 of
meiosis.
 Parts of the chromosome of non-sister
chromatids can cross over at a point called
the chiasma.
 As a result, linked alleles are separated, so
different combinations of alleles from those
parents can result.
 Crossing
over occurs during Prophase 1 of
meiosis.
 Parts of the chromosome of non-sister
chromatids can cross over at a point called
the chiasma.
 As a result, linked alleles are separated, so
different combinations of alleles from those
parents can result.
 These chromosomes are known as the
recombinants, while the original combination
of alleles are known as the parental types.
 Occurs
between the alleles for the two
linked genes.
 Occurs
between the alleles for the two
linked genes.
 The alleles on two chromosomes remain
linked and are the parental types, while the
alleles on the other two chromosomes have
crossed over, and are the recombinants
 Occurs
between the alleles for the two
linked genes.
 The alleles on two chromosomes remain
linked and are the parental types, while the
alleles on the other two chromosomes have
crossed over, and are the recombinants
 RT and rt are the parental genotypes and Rt
and rT are the recombinant genotypes.
 Fusion
of a sperm and ovum – bringing
together mum and dad chromosome and
restoring the diploid state (2n)
 Fusion
of a sperm and ovum – bringing
together mum and dad chromosome and
restoring the diploid state (2n)
 Both egg and sperm have unique combo due
to independent assortment, and
recombination.
 Fusion
of a sperm and ovum – bringing
together mum and dad chromosome and
restoring the diploid state (2n)
 Both egg and sperm have unique combo due
to independent assortment, and
recombination.
 It is change which sperm gets the fertilise
the egg – the resulting individual has it’s own
set of unique alleles, although similar to
parents, different from them too.