Where did Down syndrome first appear?

The earliest probable case of Down syndrome in the archaeological record comes from a 5- to 7-year-old child who lived in medieval France some 1,500 years ago, new research shows. Where does Down syndrome originate from? About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies …

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When do babies start showing signs of autism?

The behavioral symptoms of autism spectrum disorder (ASD) often appear early in development. Many children show symptoms of autism by 12 months to 18 months of age or earlier. How early can you tell if your baby has autism? Although autism is hard to diagnose before 24 months, symptoms often surface between 12 and 18 …

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What is secondary constriction in chromosomes?

Secondary constrictions are the constricted or the narrow region found at any point of the chromosome other than that of centromere (primary constriction). … Secondary constrictions are useful in identifying a chromosome from a set. There are either 0, 1, 2, 3, or 4 secondary constriction sites in a cell at anaphase. What is the …

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Is a population in Hardy Weinberg equilibrium evolving?

Key points: When a population is in Hardy-Weinberg equilibrium for a gene, it is not evolving, and allele frequencies will stay the same across generations. There are five basic Hardy-Weinberg assumptions: no mutation, random mating, no gene flow, infinite population size, and no selection. How do you know if a population is evolving using Hardy-Weinberg? …

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Which describes the cells at the end of meiosis 2?

Meiosis II starts with two haploid parent cells and ends with four haploid daughter cells, maintaining the number of chromosomes in each cell. What are the cells at the end of meiosis 2 called? At the end of meiosis II, we form special sex cells called gametes. This process ensures that these gametes only contain …

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