Sexual reproduction and genetic variation

Google Classroom

Review your understanding of sexual reproduction and genetic variation in this free article aligned to NGSS standards.

Key points

Many sexually reproducing organisms are diploid. Diploid organisms have two sets of chromosomes in each cell. These chromosomes are organized into homologous pairs.
In order to reproduce, diploid organisms produce gametes in the form of egg or sperm cells. These gametes are haploid. Haploid gametes have only one set of chromosomes.
Sexual reproduction happens via fertilization. Fertilization is the fusion of gametes from two parents. Fertilization leads to new, diploid offspring.
Sexual reproduction results in genetic variation, or genetic differences, between parents and offspring. Offspring inherit one set of chromosomes from each parent. So, an offspring has a mixture of chromosomes (and alleles) from its two parents.
Sexual reproduction also results in genetic variation among siblings. When a parent forms a gamete, only one chromosome from each homologous pair is included at random. So, an offspring might inherit a different combination of chromosomes (and alleles) compared to its siblings.

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Girls
Posted a year ago. Direct link to Girls's post “Can two black parents hav...”
Can two black parents have a white child?
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- ???????????
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  I believe it is possible but very rare.
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JUJUILIO
Posted a year ago. Direct link to JUJUILIO's post “Sexual reproduction is re...”
Sexual reproduction is related to genetic variation. I'll explain below.

During fertilization, each parent produce a gamete, as either an egg, (female), or sperm, (male), cells. These cells are haploid, meaning they each have one set of chromosomes, or 23 chromosomes.

Since these chromosomes come from both of the parents, they contain DNA from both of the parents. This is because chromosomes are made up of DNA, which is made up of specific parts of DNA, or genes. These genes create proteins, based upon the nucleotides in the genes. These genes carry out different functions, which are based upon the nucleotides in the genes. These proteins can cause the offspring to have different traits.

The offspring of the parents has 46 chromosomes, (23 from each parent). Because the offspring gets a mixture of chromosomes from each parent, (which effects the offspring's traits), the offspring has different traits, some from each parent.

There are so many different combinations of chromosomes that an offspring can have from its parents. This is why even siblings look different, even when coming from the same parents.

These differences between a offspring and its parent, or two siblings, can all be called genetic variation.

I hope this helped describe the relationship between sexual reproduction and genetic variation.
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- 30rimalz
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  im not reading allat ?
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preston.rose
Posted a year ago. Direct link to preston.rose's post “why do they look like x?”
why do they look like x?
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- mcbconnorj
  Posted a year ago. Direct link to mcbconnorj's post “this is from what I looke...”
  this is from what I looked up. "Chromosomes look like an x because there are two strands that are bonded together near the middle of the strand. Proteins are what holds these two strands together, which is called the centromere. When looking at a karyotype image of all 23 pairs, you can see how each strand look like an x because of that bond." so its basically saying that they're connected together by some strands of proteins.
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GabrielleS
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why a black dad and a white mom birth a child that can end up white?
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- Deni
  Posted a year ago. Direct link to Deni's post “depends on gene transfer”
  depends on gene transfer
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RavenP
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Is this how babies are made?
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- EpSiLoN
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  That my friend, is a question for your parents! :)
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Gavin Haase
Posted a year ago. Direct link to Gavin Haase's post “what happenings if none o...”
what happenings if none of the sperm makes it pass the uteri's
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- Z
  Posted a year ago. Direct link to Z's post “then no baby”
  then no baby
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8703775
Posted a year ago. Direct link to 8703775's post “what are gametes”
what are gametes
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- Speedyspeedcuber
  Posted a year ago. Direct link to Speedyspeedcuber's post “A gamete is a reproductiv...”
  A gamete is a reproductive cell of an animal or plant. In animals, female gametes are called ova or egg cells, and male gametes are called sperm. Ova and sperm are haploid cells, with each cell carrying only one copy of each chromosome.
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josiah
Posted 5 months ago. Direct link to josiah's post “If i'm 2% white and my wi...”
If i'm 2% white and my wife is 100% black would it be possible for my child to be white?
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- Menschinator
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  It all depends on dominant genes...
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MohamedJ
Posted a year ago. Direct link to MohamedJ's post “How is it possible for a ...”
How is it possible for a person to get the same eye color or hair color from two generations ago.
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- jxhpiano
  Posted 2 days ago. Direct link to jxhpiano's post “I bet it is but very, ver...”
  I bet it is but very, very, very, very, (imagine a lot of very’s here) rare.
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AndersonA
Posted a year ago. Direct link to AndersonA's post “Never”
Never
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