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Scientists discover guidance system for migratory songbirds
24 days ago
- Migratory pied flycatchers use a combination of genetics and environment to determine their wintering destinations.
- Birds from different European populations follow consistent, non-direct routes to Africa, with Siberian birds taking a long detour via Spain.
- Experiments moving Dutch flycatchers to Sweden showed wintering location is partly inherited and partly influenced by upbringing.
- Migration routes are shared, but the length of the journey, not the direction from breeding areas, may be fixed.
- The behavior is not learned from parents, which is key for understanding adaptation to climate change.
Mystery of India's red-haired child unlocks hidden colour genes
23 days ago
- A red-haired girl in India had a rare mutation in the MC1R gene (p.Ala291Asp), different from European variants, inherited from both parents who have black hair.
- Researchers identified 21 novel or rare MC1R variants in India, with nine exclusive to Indians; two (p.Ala57Thr and p.Ile40Thr) are linked to skin cancer risk and other traits.
- A non-coding variant (rs3212363) associated with lighter skin was confirmed in high frequency among the Bodh population of Ladakh, showing varying frequencies across India.
- The study reveals South Asia's complex genetic architecture for pigmentation, influenced by migration and adaptation, with MC1R now a key gene alongside others like SLC24A5.
- Findings challenge assumptions about adaptation to UV radiation and highlight independent genetic evolution in India, offering insights into rare diseases and global biological diversity.
Why Am I Left-Handed?
14 days ago
- Left-handedness involves mirror-writing tendencies and practical inconveniences like ink smudges, but also offers a sense of community among notable individuals.
- Historically stigmatized, left-handedness has been suppressed through forced switching and negative language associations, with ongoing cultural taboos in regions like Africa.
- Handedness is not purely genetic, with only a 25-30% chance for left-handed children of left-handed parents and a 20-30% chance in identical twins, indicating developmental randomness.
- Fetal studies show hand dominance emerges before brain-limb connections, originating in spinal cord gene expression asymmetries, not brain-driven processes.
- Genetic factors include variants in tubulin genes, which influence microtubule structure and are linked to increased left-handedness and neurological conditions like schizophrenia and autism.
- Evolutionary theories suggest right-handedness may have emerged for combat advantages, such as protecting the heart, with left-handers persisting due to surprise benefits in fights.
- Cultural norms and hygiene practices, like hand-use taboos, may reinforce handedness biases, contributing to survival benefits and stigma over millennia.
- Handedness reflects a complex interplay of biology, genetics, evolution, and culture, integral to human uniqueness without a single definitive explanation.
Genetics and intelligence differences: five special findings
13 hours ago
- Intelligence is a highly heritable trait, with heritability increasing from about 20% in infancy to as much as 80% in later adulthood.
- Intelligence captures genetic effects common to diverse cognitive and learning abilities, with genetic correlations around 0.60 or higher.
- Assortative mating for intelligence is high (spouse correlations ~0.40), which increases additive genetic variance in the population.
- The genetics of high intelligence are continuous with normal variation; high intelligence is just as heritable as the rest of the distribution.
- Intelligence shares genetic causes with education and social class, linking genetics to social mobility and health outcomes.

genetics

Scientists discover guidance system for migratory songbirds

Mystery of India's red-haired child unlocks hidden colour genes

Why Am I Left-Handed?

Genetics and intelligence differences: five special findings