Question

Which method can be used to determine whether two sisters are identical twins? (A) Check to see whether their blood glucose levels are identical. (B) Compare their physical appearances to see whether they look alike. (C) Check their family history. (D) Do a DNA analysis.

Short answer

(D) Do a DNA analysis.

Step-by-step solution

Analyzing the given options

Out of the four given options, we need to identify the method that can confirm that two sisters are identical twins.

Understanding identical twins

Identical twins are formed when a single fertilized egg splits to form two embryos with the same genetic material. This means that identical twins have the same DNA.

Evaluating the options

(A) Blood glucose levels can be affected by various factors and are not related to being identical twins. (B) Physical appearances can be similar but might not be enough to confirm identical twins as some features are also influenced by environmental factors, such as diet and lifestyle. (C) Family history provides information about their ancestry but cannot confirm if they are identical twins.

Choosing the correct method

(D) Since identical twins have the same DNA, DNA analysis would be the most accurate and reliable method to determine if two sisters are identical twins. Therefore, the correct answer is (D) Do a DNA analysis.

Key concepts

Identical Twins Determination

When considering how to determine whether two individuals are identical twins, we delve into the fascinating world of human genetics. Identical twins result from a single fertilized egg that divides and develops into two separate embryos. These embryos share the same genetic composition, making their DNA virtually identical.

To accurately establish whether two sisters are indeed identical twins, scientists and geneticists rely on DNA analysis. While physical appearance and familial traits can provide hints, they are not definitive due to the influence of environmental factors and the possibility of coincidental resemblance in fraternal twins or siblings. Only DNA analysis can provide the conclusive evidence needed to determine identical twinship, as it compares the specific sequencing of genetic material.

DNA Analysis

DNA analysis is a powerful tool in modern science, allowing us to unlock the genetic codes that define living organisms. It involves examining the nucleotide sequences within a DNA molecule to understand genetic relationships, mutations, parentage, and much more. For identical twins, DNA analysis focuses on comparing their genome sequences. Since identical twins originate from the same egg, their genomes will match almost exactly, barring any mutations that might have occurred post-zygote division.

This process of analysis uses techniques such as Polymerase Chain Reaction (PCR) and gel electrophoresis to amplify and then differentiate DNA fragments, thereby facilitating an in-depth comparison. Such precise genetic fingerprinting is the reason DNA analysis stands as the gold standard in confirming identical twins.

Genetics

Genetics is the biological science that explores how traits are inherited and expressed in living organisms. It investigates how parents pass on genes to their offspring through units of heredity known as alleles.

In human genetics, identifying identical twins is akin to finding two genetic mirrors. This field explains why siblings, including fraternal twins, can share some traits while exhibiting distinct differences due to the unique combination of genes they inherit from each parent.

• Genetic inheritance follows patterns, with dominant and recessive alleles influencing how traits are expressed.
• Genetic variation is the cornerstone of diversity within and between species.
• The study of genetics is central to understanding hereditary diseases, evolution, and biotechnology applications like gene therapy and genetic engineering.

Through genetics, we appreciate the complexity of life and the subtle nuances that dictate whether two individuals are identical twins or not.

Biology Concepts

Biology provides the concepts necessary to appreciate the intricacy of life at the molecular, cellular, and organismal levels. Core biology concepts relevant to the determination of identical twins include cellular division, particularly meiosis and mitosis, and embryological development.

Cellular Division

Cellular division is key to understanding how identical twins form. While meiosis results in genetically diverse sex cells, mitosis leads to the replication of cells with identical DNA – which is what happens when the zygote divides to form twins.

Embryological Development

During embryogenesis, the split that results in identical twins typically occurs early, and understanding this stage is vital for grasping how identical twins share their genetic makeup.
Biology not only helps us to comprehend the broader concepts but also frames our understanding of DNA analysis and genetic inheritance patterns within the context of living organisms’ growth and reproduction.