Theme A - Unity & diversity

Unlocking The Mystery Of Chromosome Evolution

608 words

4 mins read

Last edited on 14th Jun 2024

Karyotyping is a process where chromosomes become visible when cells are dividing, with the most clarity during the metaphase. Think of this as the cell's family photo shoot - where each member of the family (chromosomes) comes together and poses for a picture!
To get the chromosome picture, cells are stained and placed on a microscope slide, and then gently burst to spread the chromosomes. It's like a chromosome firework show!
Using a microscope, scientists can find cells where the chromosomes don't overlap, and take their photographs. It's just like sorting through a pile of family photos to find the perfect shot.
With digital technology, we can now arrange chromosomes in an orderly manner based on differences in banding patterns, size, and centromere position.
- Banding patterns are like the distinctive fashion styles of each chromosome.
- Size differences are evident, just like in a family, where the eldest (chromosome 1 in humans) is the largest, and the youngest (chromosome 21 in humans) is the smallest.
- The centromere, holding the two chromatids of each chromosome together, varies in position, just like how in some families, the mom or dad might be the more dominant parent!
The sorted image of the chromosome is called a karyogram. So, if karyotyping is the family photoshoot, the karyogram is the final family portrait!

Human cells contain 46 chromosomes, while our primate cousins - chimps, gorillas, and orangutans - carry 48. Imagine going to a family reunion and finding out you have fewer cousins than you thought!
One hypothesis suggests that our chromosome 2 is the result of two primate ancestor chromosomes merging. Imagine if two of your cousins decided to become a team and henceforth be known as a single entity!
This hypothesis can be tested by comparing human chromosome 2 with chimpanzee chromosomes. If they show similar banding patterns, it would suggest a shared ancestry.
Moreover, if this fusion happened, we would expect to find remnants of the 'glue' (telomeres) that held the original chromosomes together at the fusion point.
Also, there would be remnants of a second centromere because each original chromosome would have had one. It's as if, when two cousins team up, one can't simply forget their old house; there would be some signs left behind.

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Biology HL

608 words

4 mins read

Last edited on 14th Jun 2024

Karyotyping is a process where chromosomes become visible when cells are dividing, with the most clarity during the metaphase. Think of this as the cell's family photo shoot - where each member of the family (chromosomes) comes together and poses for a picture!
To get the chromosome picture, cells are stained and placed on a microscope slide, and then gently burst to spread the chromosomes. It's like a chromosome firework show!
Using a microscope, scientists can find cells where the chromosomes don't overlap, and take their photographs. It's just like sorting through a pile of family photos to find the perfect shot.
With digital technology, we can now arrange chromosomes in an orderly manner based on differences in banding patterns, size, and centromere position.
- Banding patterns are like the distinctive fashion styles of each chromosome.
- Size differences are evident, just like in a family, where the eldest (chromosome 1 in humans) is the largest, and the youngest (chromosome 21 in humans) is the smallest.
- The centromere, holding the two chromatids of each chromosome together, varies in position, just like how in some families, the mom or dad might be the more dominant parent!
The sorted image of the chromosome is called a karyogram. So, if karyotyping is the family photoshoot, the karyogram is the final family portrait!

Human cells contain 46 chromosomes, while our primate cousins - chimps, gorillas, and orangutans - carry 48. Imagine going to a family reunion and finding out you have fewer cousins than you thought!
One hypothesis suggests that our chromosome 2 is the result of two primate ancestor chromosomes merging. Imagine if two of your cousins decided to become a team and henceforth be known as a single entity!
This hypothesis can be tested by comparing human chromosome 2 with chimpanzee chromosomes. If they show similar banding patterns, it would suggest a shared ancestry.
Moreover, if this fusion happened, we would expect to find remnants of the 'glue' (telomeres) that held the original chromosomes together at the fusion point.
Also, there would be remnants of a second centromere because each original chromosome would have had one. It's as if, when two cousins team up, one can't simply forget their old house; there would be some signs left behind.

Dive deeper and gain exclusive access to premium files of Biology HL. Subscribe now and get closer to that 45 🌟