101An introduction to what is and how does it work?Teach ubraintv-jp.comLessons and also teaching toolsConceptual framework
Teaching guidesDealing v objections come

Recombination introduces brand-new gene combinations into populations.

You are watching: How many chromosomes does a human egg have

Here is a quick and also dirty testimonial of the genes of sex-related reproduction. We’ll use person reproduction to anchor this since it’s a acquainted topic, yet the simple ideas move to various other sexually reproducing organisms.

Genes are situated on long chains the DNA called chromosomes.Humans have 23 pairs of chromosomes: one member of each pair to be inherited from the mother and the various other from the father. Correspondingly, we have actually two execution of every gene, one from the mother and also one from the father.

If human being reproduced by taking 23 bag of chromosomes indigenous the mother and also 23 bag of chromosomes indigenous the father, the infant would have too plenty of chromosomes (46 pairs). For this reason eggs and sperm bring only half the usual variety of chromosomes — simply 23 unpaired chromosomes, carrying one version of each gene. Once the egg and also sperm acquire together, the baby receives the regular 23 suitable pairs.

Here’s how egg and also sperm are produced:

The parental cell very first copies each chromosome, leaving the duplicate bag attached to one another.

See more: Lyr I Want To See You Tonight England, I'D Really Love To See You Tonight


Producing eggs and sperm is our first opportunity because that mixing and also matching genes. As soon as the mommy makes one egg, her chromosomes an initial find your matched partners and exchange some DNA through each other. That’s referred to as recombination. Because of this shuffling, genes from the mother’s mom and genes from the mother’s father deserve to wind up next to one another on the very same stretch the DNA. (The very same thing happens in the father’s sperm.)


Only after chromosomes recombine perform they segregate into various egg cells, so that each egg cell end up through one variation of each chromosome.In action two that meiosis, every diploid chromosome above is traction apart right into separate daughter cells, generating four separate cells, every containing simply one copy of every gene:


When egg and sperm meet, the baby inherits a combination of genes that is completely unique: it carries versions of genes from all 4 grandparents plus any kind of mutations that arisen when the mother and also father were making the egg and also sperm.